[PROPOSAL] enable gerrit buildbot trigger for all in group commiter

Hi,

so this is a proposal to enable the ability to trigger a build for all in the
group commiter and not some rather restricted and nonobvious set of people
(including me).

Securitywise, this presents no new risks as everyone in group committer already
has the ability to push stuff to master which is then executed by tinderboxes.

The restriction to just a few people being able to trigger the build was
originally done to prevent the bots to be overwhelmed resourcewise -- but I think
the explicit and manual triggering of builds is already enough to ensure that,
if everyone is acting responsible. In light of the cultural tradition in the
LibreOffice project to be optimistic and supporting about contributor skills
and judgements, I think the limitation to a restricted and arbitrary set of
people is overly cautious. Anybody, who has commit access to master should be
able to trigger a build, if e.g. asked about it on IRC.

This would work as follows:
- Random person asks "hey can you trigger my change <gerrit-URL>"
  (or someone with commit access want to test a change on all platforms before
  it hits master)
- Random commiter (that is a person with direct push-to-master permissions):
  - checks the change not to contain an evil exploit trying to harm a
    tinderbox (no full review beyond that needed yet)
  - runs "ssh logerrit buildbot show -p core" to see if there is a huge backlog
    on the builders already
  - runs "ssh logerrit buildbot schedule -p core SHA1" the schedule the build

I dont think we should monopolize the access to these boxes, if it is used
responsible by everyone. If that is the case we will be quicker in response
time, without wasting these valueable ressource either by under- or overusing
it. If it is not used responsibly, we can still revert to the old subgroup
until we have the builderboxes.

Opinions?

Best,

Bjoern