Search commits based on LDAP name

Proposal

This feature proposal is for enabling the option to filter commits by LDAP name instead of GitLab's user name.

When searching commits on Gitlab, it is possible to filter them by author ('Search by author' option).

For example:

• When an author is selected (e.g. Ricardo Leite), we get results filtered for this author's name (https://PROJECT_URL/-/commits/master?author=Ricardo%20Leite.

When we are using LDAP to sync users and we use LDAP name as author name when we commit the code, we want to be able to search the commits based on LDAP name, not user name (e.g. https://PROJECT_URL/-/commits/master?author=rleite, where rleite is LDAP name of the user Ricardo Leite).