InlineEdit: Add support for changing commit message

Change-Id: I27fe806d699e2980f2e7eab07617df17edcb4b13
InlineEdit: Add REST endpoint to modify commit message

Change-Id: I7e2745570de7ddce0f74533f2c5be40f42065a60
InlineEdit: Add REST endpoint to retrieve commit message

Change-Id: I9017df268614e8035513af173a7067a8aa10fcec
Merge changes from topic 'inline-3'

* changes:
  InlineEdit: Add REST endpoint to retrieve commit message
  InlineEdit: Add REST endpoint to modify commit message
  InlineEdit: Add support for changing commit message
InlineEdit: Add support to change commit message from the UI

Change-Id: Icdaa6a4e2e79df60ad07594526c2ace5b7999842
InlineEdit: Support change edits on draft changes

Publishing change edit on draft changes preserves draft status of the
change.

Change-Id: I8cfa1f803a2366da99b81a17a6d20bb6f25a982e