Provide a configuration to prevent authors from reviewing their own work

Change Request has been implemented in a way such as authors of a CR cannot review their own work. I consider this feature as very important personally because one goal of CR is to ensure to get reviews on the work.
However, this feature might make difficult to discover the extension capabilities since once installed it needs the collaboration of another user even for testing it.
So in order to change that I'll provide by default the capability for authors to review their own work, with a configuration to prevent that behaviour.