Move issues/mr filter to partial

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Add author filter for issues & merge requests pages

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
More tests for issues finder

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

Author filter for issues and merge requests pages

This is first step in implementing #1604

See merge request !1309