Split merge request coffee

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Allow change assignee/milestone from MergeRequest show page

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
 Merge branch 'feature/mr_context' into 'master'

Allow change assignee/milestone from MergeRequest show page