Made 'auto-reply' optional for Phone/Custom tickets

As mentioned in IdeaScale # 366 Option to suppress auto responses to new call tickets
https://otrsteam.ideascale.com/a/dtd/Option-to-suppress-auto-responses-to-new-call-tickets/104579-10369

SystemConfig Core::PostMaster has now the setting:

AutoResponseForWebTickets

Defaults: YES # to be backward compatible

If this option is set to 'Yes', tickets created via the web interface, via Customers or Agents, will receive an autoresponse if configured. If this option is set to 'No', no autoresponses will be sent.
Added dropdown of available transition actions in dialog.

Today I'm attending Process Management training.
I found it very unpleasant to have to type in

  Kernel::System::ProcessManagement::TransitionAction::TicketStateSet

every time I want to add a transition action. It's a long string and it's error prone.
I added a selection that shows a list of available transition actions.

Of course you still need to know what key-value pairs are needed as arguments for the
transition action, but at least entering a new transition action now is a little more
convenient.
Added Queue in SystemAddres Overview.
do not limit deletion of attachments. If user tries to delete an attachment above the limit (sometimes 16, sometimes 32), the message is sent. She might not have added all information she wanted to add.
Corrected perldoc.
Reverted fix for bug#7110 due to QA fail.
Reverted fix for bug#7110 due to QA fail.
Added test.
Partial fix for bug#4465. WIP.
Updated module description.
Updated module description.
Fixed bug#8273 - Copying text in preview mode not possible.
Fixed bug#6502 - AdminQueueAutoResponse interface changes.
Fixed bug#9233 - GenericInterface (TicketCreate and TicketUpdate can't set a defined CustomerID).
Improved parameter quoting
UserIDs are not ints here!
Fixed CustomerGroup Caching.

CustomerGroup caching was using the same cache keys as the 'regular'
groups.
This resulted in problems with customer group support; apparently
customer groups are not very widely used.

Fixes bug#9539 - Cannot Send Notification to a Group of Customer Users
http://bugs.otrs.org/show_bug.cgi?id=9539
Fixed bug#9481 Possible to select invalid services in SLA admin screen.
Fixed wrong comment position.
Merge branch 'feature-mb-showqueue-master' of https://github.com/mbeijen/otrs