Use LDAP to add member permissions to individual projects

Description

LDAP groups can only be added to GitLab groups. Members of an LDAP group can only have their accesses assigned at the group level. While LDAP users can be added to projects, like normal users, there are certain workflows where it would require synching to individual projects.

From https://gitlab.zendesk.com/agent/tickets/76822:

Scenario: we have a large project. There are several teams working on different repositories. Some of these teams are from external companies and should not see everything.

Proposal

Add the ability to sync member permissions to individual projects.