Example use case %staff.name  %team.name ... etc.

Change enableGroupMembership() to isGroupMembershipEnabled(). Improve getMembers function. Make sure  is an array in updateAllowedGroups

- Move access to it's own table.
- Refactor what department membership means in relation to group access

And fix various lint issues, include adding the yet-undefined-but-referenced
deleteAttachment() function for canned-responses and faq entries

And correct several undefined function errors from several source files. So
while function names in PHP are considered case-insensitive, it still makes
sense to use consistent camel casing for both defining and calling methods.
The lint test searches the code base for method calls, and then searches the
code base again looking for a function definition matching the name of the
function invoked. It's not failsafe, because it doesn't detect the class
from which the method should belong, so it's likely to have false negatives.
Furthermore, it won't work well for PHP 5 where several classes are built
into PHP (and aren't searchable in the osTicket code base).

Remove the include/staff/api.inc.php as it no longer appears to be used (and
contains references to undefined methods).