Add audit event entry when a group share is added/removed to a project

Zendesk issue: https://gitlab.zendesk.com/agent/tickets/14626

When a project owner adds or removes a group share, an entry should be added to the audit events. Changing group shares changes the people that have access to a group so it should be recorded.

• Include:
  • Adding or removing sharing a project with a group

Note: This is available already for sharing a group with a group. See https://docs.gitlab.com/user/compliance/audit_event_types/#user-management. We need to add the same for projects.