[TYPO3-core] Git Commit Messages documented

[Ernesto Baschny [cron IT]]

Hi,

since there have been some discussions regarding the commit messages and
different styles being used, I adapted our currently "official"
documentation about it, to reflect the most recent facts:

http://wiki.typo3.org/CommitMessage_Format_%28Git%29

Please feel free to discuss the result here.

My rationale:

A change is either [TASK], [BUGFIX], [FEATURE] or [API]. All other flags
([!!!], [CONF], [DB]) are just add-ons which describe the issue further.
I think especially the [DB] one is important so that people know when a
DB-UPDATE is required.

I would also like to see the commit message stripped off superfluous
information that is already present in the issue tracker (like "How to
reproduce" etc). Repeating it is useless. Just use the message to
explain the "change" itself, if required.

The subject should always be in *present tense*, and explaining what is
changed by this commit. Here are some examples:

* [BUGFIX] Throw HttpStatusExceptions in tslib_fe
* [FEATURE][CONF] Add option to hide BE search box in list mod
* [TASK][!!!] Move Advanced Frontend Editing to TER
* [TASK][!!!] Remove t3lib_sqlengine
* [API][!!!] Remove deprecated method redirect() from t3lib_userAuth
* [API] Create an Exception hierarchy for HTTP Status Exceptions

i.e. removing deprecated stuff will always be "[API][!!!]", introducing
new API methods would be a "[API]".

Of course there might be edge cases (a new feature also adding new API),
in which case the [FEATURE] should have priority.

I also documented the recently discussed "Release:" tag which would help
us track merged reviews in Master which should also be backported to
older releases.

Cheers,
Ernesto