Refinements to allow direct commits to master, build skips with auto-merge

This MR refines a bit the commitfile command to introduce:

• Better log messages, more pertinent and with more information about what it is really doing
• The ability to commit directly to master (which is the default behaviour now)
• In merge-request creation mode, if [ci skip] or [skip ci] is detected on the commit message, and auto-merge is set, then merge immediately