If failing to import file content data, drop contents imported thus far

This patch adds an export+import method to the file command line module. The
file export is agnostic of the file storage backend. It writes the files
with the %file record data to standard-out or to the file given by the -f
option. The file is a considered a stream and can quietly be compressed and
can be read back in as a stream (no seeking is performed in the import
process).

Don't add to endTime if not already set

forms: Use form's name as the heading.

Reviewed-By: Jared Hancock <jared@osticket.com>

filter: Implement ban on reply-to email address

Reviewed-By: Peter Rotich <peter@osticket.com>

Show the form title on edit instead of "Custom Form" - which can be
misleading since the user might be editing a built-in form.

If a new ticket is assigned to both an individual agent and a team, do not
send the email alert to the team lead or the team members.

email: Send staff alerts from the department email

Reviewed-By: Peter Rotich <peter@osticket.com>

Properly escape text bodies for canned responses

Reviewed-By: Peter Rotich <peter@osticket.com>

files: Provide unified download script

Reviewed-By: Peter Rotich <peter@osticket.com>

This patch changes the ticket filter system so that it can be recursively
looped to allow for banning and matching on the reply-to address and name.

This script adds a single download script, 'file.php', which provides access
to files of all types to all users. It uses a HMAC signature system with an
expires time, which allows signed URLs to be sent to external users.

This also fixes an issue with the Http::cacheable() method, where the
last-modified and Etag headers were not properly compared, which resulted in
permanent cache misses by the client.

Sanitize query strings

Reviewed-By: Jared Hancock <jared@osticket.com>

Use http::build_query instead of inline urlencode

Retire l.php

Reviewed-By: Jared Hancock <jared@osticket.com>

filters: Fix several small, major issues

Reviewed-By: Peter Rotich <peter@osticket.com>

  * Fix incorrect mapping to user email address
  * Fix early rejecting of tickets — even if a filter earlier in the
    matching filter list had "stop on match" set
  * Fix ::stopOnMatch referring to incorrect db field

The new logic abandons the early rejection logic in ticket create. Instead,
the normal validation is completed as usual. Thereafter, the filter is
initialized and applied to the ticket. Upon rejection, a RejectedException
is thrown by the ::apply() method of the TicketFilter. The Ticket::create()
method will handle the exception and reject the ticket.

Stop trampolining links via l.php. It was necessary before in order to avoid
the potential of leaking ticket number & email. The authentication mechanism
in place now redirects on successful login.

This is necessary so we can sanitize/encode inputs.

This patch changes the default formatting for text bodies used in emails,
ticket thread, and canned response quoting so that white-space in text
bodies is properly preserved. Previously, the text was treated as raw HTML
and was not properly escaped, nor was the original whitespace preserved.

This patch adds a ::getAlertEmail() method to the Department class, which
allows administrators to use the department email address (normally for
replies) as the alert email address. If not specified, the system alert
email address is retrieved instead, automatically.

date search fix

Reviewed-By: Peter Rotich <peter@osticket.com>

staff: Ensure an active admin always exists

Reviewed-By: Peter Rotich <peter@osticket.com>

Record closed-by if opening a ticket with state closed

Reviewed-By: Peter Rotich <peter@osticket.com>

i18n: Fix display of language selection for new templates

Reviewed-By: Peter Rotich <peter@osticket.com>

ui: Implement "enable canned responses" config option

Reviewed-By: Peter Rotich <peter@osticket.com>

orgs: Add support for organization variables

Reviewed-By: Peter Rotich <peter@osticket.com>