Add option to mass clean up mail Queue

[dragoangel]

Currently if you have mail in queue to remove it you need open each email and click on small (gray-on-gray) remove from queue hypertext.

• The search is missing on queue screen.
• The checkbox to bulk operation is missing with option to check all on screen.
• The option to clean ALL queue or ALL queue for one credentials is missing.

For what this needed? For example:

• some user register on site with not existing incorrect email (f.e.: yahoo.net, hmail.com, etc) and try "verify his email" clicking on it 100 times. You want remove this from Postal - but it pain to remove each individual email.
• rarely bad case: in theory someone still\bruteforce your credentials and abusing your setup. You disabled credentials but in queue is million of mail which will try to be delivered. Without purge queue how you will clean up this? Remove and recreate all server?