Restore `timeout` option for Drush command

[edit] ignore this post - test suite does not pass. See #3.

We needed this functionality so I've created a patch.

Attached and tested with Drush 9.

Usage:
drush advancedqueue:queue:process queuename --timeout=60
where:
- {queuename} is the id of your queue, as per the queue_id column of the advancedqueue database table, or `id` in the config yml
- --timeout={x} where {x} is a value in seconds. e.g. 60 = one minute

Tested. It works as expected.

Re-rolled patch

This, according to #4

Thanks everyone!

@jcnventura: Did you really test the patch? Also, please pay attention to the coding standards as they're comments longer than 80 characters for example, empty whitespaces... And I'm suspecting this change to cause #3319627: Upgrading from RC4 to RC5 slows down or stops cron running..

Reverted this, as it introduced the following problem from #3319627: Upgrading from RC4 to RC5 slows down or stops cron running.

At admin/config/system/cron set detailed cron logging.

At admin/reports/dblog "Starting execution of advancedqueue_cron()." for up to an hour.

Attempting to rerun cron from drush or admin ui results in, "Attempting to re-run cron while it is already running."

This happens on two virtually identical sites, dev and staging, whilst on the production site with rc4, cron runs normally with advancedqueue cron completing and stepping onto the next process within milliseconds.

This patch should only really use the timeout option to set the processing time and not try to daemonize the queue processor.

Modifying #4 this to only set the queue max processing time. Making the processor be idle in the background until that time is reached should be handled in #3275594: Allow processor to keep running when queue gets empty.