Git commit message checking

[Ed Tanous]

A review [1] is proposing deploying gitlint widely across the project,
to improve the response time for feedback that is easily caught by CI.
There are a few repos that have already enabled this check for a few
months, and we have worked through a few minor issues, but largely
it's been positive in giving faster response times when a code review
gets pushed that doesn't meet our guidelines.  A few folks have
requested that we roll this out more widely, so I'm signal boosting a
bit to make sure folks are aware of it, and those that have reviewed
the patchset in the past have a chance to weigh in to see if we can
get consensus, before doing something that would significantly impact
folks workflows.

For reference, our commit message expectations are documented here
[2].  The intent is that this isn't changing any existing rules, but
only automating the rules we already have.  The gitlint rules we have
are checked into openbmc-build-scripts [3], but can generally be
tested with openbmc-build-scripts, without any need to run gitlint
directly.

Overall, I'm looking for input on whether this is the right direction,
whether this will help folks, and make sure this won't be an
impediment.  Once this is deployed, we will try to monitor for
false-positives, but please feel free to reply to this thread if you
see any, and we will take the appropriate action.

Thanks,

-Ed

[1] https://gerrit.openbmc.org/c/openbmc/openbmc-build-scripts/+/56592
[2] https://github.com/openbmc/docs/blob/fa1cca721c824446929705bac1654ec7ae0973fe/CONTRIBUTING.md#formatting-commit-messages
[3] https://github.com/openbmc/openbmc-build-scripts/blob/master/config/.gitlint