This changes the queue counts shown at the bottom of the page to no longer be
calculated using the SQL_CALC_FOUND_ROWS method of MySQL. Such is very slow for
large recordsets. Instead, a rough count is computed based on the total number of
tickets in the queue without respect for staff access. This is the fastest way to
get a maximum number of possible tickets to be shown. The pagenation interface
should be changed to show only NEXT and PREVIOUS pages where the rough estimate can
be used to provide a rough idea of whether or not another page of data would be
available.

Furthermore, if APCu is available, the rough count is stashed and kept between
requests so that the rough counts do not need to be re-tallied until they would
change from a ticket state change.

Another optimization might be to increment and decrement the queue rough counts when
tickets are created or change states. In such a case, it could be identified which
queues the old ticket would have been (and decrement the count) and which queues the
updated ticket would be in (and increment the count).

If APCu is available, then the queue counts can be cached between requests.
They are automatically cleared and recalculated if the status of a ticket
changes or if a queue or saved search is edited. Otherwise, the queue counts
will expire after an hour and be recalculated anyway.

Somehow on large datasets (like >1M tickets), MySQL can get confused on which
index will provide the best performance. Generally, as systems age, they will
have significantly more closed tickets than open ones. Therefore, it should be
safe to assume that scanning the `status_id` index on the ticket table for
`open` tickets would be the fastest way to arrive at the sort-of short list of
tickets which should need to possibly be aged.

The commit fixes queues display and sorting.

* Require keyword search term to be 3 words or less
* Show keyword search option on Advanced Search dialog

This commit makes Primary Queues buckets for sub queues with forced inheritance of
criteria. Primary queues are now hidden unless there are no sub queues
attached. Agents can still get to primary queue by clicking on it.

The commit also adds default sub queues for Closed queue, utilizing DateTime
periods.

This commit ensures that we use the correct disposition for downloading files.

This commit ensures that we will always get the correct attachment name regardless of if the file content is the same. Additionally, it ensures that the file_ids for attachments are compared in the correct order (elseifs)

This commit ensures that we will always get the correct attachment name regardless of if the file content is the same. Additionally, it ensures that the file_ids for attachments are compared in the correct order (elseifs)

- Make sure we keep attachments in the session even if the page refreshes to display an error message
- Reverse the array of files to be id => name instead of name => id
- Make sure we retain the old ticket or task id if we encounter an error while trying to create a ticket or task from a thread entry
- Make sure we have a valid fileId before returning file info
- Make sure we can still add files for Canned Responses (id and name flip issue)
- Make sure we can still add attachments to Internal Notes for Tickets and Tasks

Add support for periods to DateTimeField allowing the search on range of
dates based on set period like 'Today', 'This Quarter' or 'Last Week' etc.

This commit ensures that we will always have the correct display of values for the Ticket Source regardless of if the key and value differ.
Ex: if we had a Ticket Source that contained a space in the value, the key would be camelcased

This commit fixes an issue we had where the bolding on the Ticket Number and Subject columns of advanced searches showed the opposite of what they should have. We instead want them to be bold if the Tickets are Unanswered.

- Let validate_actions pass if we are trying to disable/archive a Help Topic so that the filter flag can be set.
- Make sure we do not throw validation errors when deleting a filter action. Just delete it.

Only use field display when fetch value is not string

If a Help Topic is disabled or archived and it is also selected as the Help Topic for an Email, make sure we do not remove that Help Topic from the Email. Instead, if that email receives a Ticket, we should just assign the ticket to the Default Help Topic. If there is no Default Help Topic, the Ticket will not have a Help Topic at all.

Pass name to Queue Column Annotation annotate routine

This addresses a careless copy/paste mistake made with 4496

This commit adds the ability for DatetimeField to specify format string -
this is useful when the field display requires specific format different
from the system defined formats. For example during export.

This commit addresses longstanding memory and speed issues with ticket
export especially when exporting large set of tickets.

The implementation borrows heavily on Custom Columns, which introduced the
idea of using placeholder field to parse the data from query (db) instead of
making models to do the  parsing which led to related models getting fetched
too -- and hence the memory issues.

The commit also addresses caching of choices for selection fields and such
to avoid expensive trips to database for each row!

This addresses an issue introduced with 4426 that references an undefined
class.

This commit addresses a case where a large thread entry body (emailed) is
stored as a file, when fetching it we have to make sure we're only fetching
plain text/html and not attachment files.

This is necessary because ticket filters or API can set an invalid help
topic id. Either deleted or no longer active.

This addresses an issue where personal queues are duplicated in the main
queue sub-list.

This commit fixes an issue where we were not emailing attachments for initial responses when creating a Ticket.

This commit fixes an issue we had with adding a Filter Action to Send an Email. We had an option at the top for 'Default System Email', however, it did not have the Email ID or address for the system email and would throw an error if chosen. Now, we just retrieve the emails with their IDs and values with the Default System Email being the initial value selected in the list of options.

This commit further corrects issues where emails were being sent out with names being improperly formatted if the name format is set as 'Last, First' or if it has special characters.

This addresses an issue introduced with 4124 where searching for a Selection
Field with the criteria "does not have a value" throws an `implode()`
warning.

This improves accessibility by adding screen readable labels to ticket
actions that don’t already have them.

This commit stores internal notes if an Agent includes one while creating a Thread Referral.

This addresses issue 4473 where users creating a ticket with the Help Topic
preselected shows a validation error for the Issue Summary field. This is
due to the new `getFormName()` function that creates new field form names
based on the user’s/agent’s session. When the Help Topic is preselected,
`_form` is not set for each field so the hashed name of the fields before
ticket submit is different than after ticket submit.

This addresses an issue where `$_SESSION[':form-data']` files are not
including the new filenames.