Add search mode option to /api/repo/search (#2756)

* Add repo type option to /api/repo/search

* Add tests and fix result of collaborative filter in specific condition

* Fix/optimize search & tests

* Improve integration tests

* Fix lint errors

* Fix unit tests

* Change and improve internal implementation of repo search

* Use NonexistentID

* Make search api more general

* Change mirror and fork search behaviour

* Fix tests & typo in comment

models/fixtures/team_user.yml

@@ -38,4 +38,10 @@
   id: 7
   org_id: 17
   team_id: 5
-  uid: 18
+  uid: 18
+
+-
+  id: 8
+  org_id: 19
+  team_id: 6
+  uid: 20