Add option to RawBlameRequest to support --ignore-rev-file

Hi!

This MR adds the ability to optionally specify a revision parameter (see SPECIFYING REVISIONS in man 7 gitrevisions) to RawBlame() allowing the use of a .git-blame-ignore-revs file and loads it into the git blame command using --ignore-revs-file

An example would be a RawBlame ignore_revisions_blob parameter of refs/heads/master:.git-blame-ignore-revs

Related to gitlab#31423 (closed)