* fix units permission problems

* fix some bugs and merge LoadUnits to repoAssignment

* refactor permission struct and add some copyright heads

* remove unused codes

* fix routes units check

* improve permission check

* add unit tests for permission

* fix typo

* fix tests

* fix some routes

* fix api permission check

* improve permission check

* fix some permission check

* fix tests

* fix tests

* improve some permission check

* fix some permission check

* refactor AccessLevel

* fix bug

* fix tests

* fix tests

* fix tests

* fix AccessLevel

* rename CanAccess

* fix tests

* fix comment

* fix bug

* add missing unit for test repos

* fix bug

* rename some functions

* fix routes check

* 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

* Add more repo search tests

* Add and fix /api/repo/search integration tests

* Add owner to access table for organization repositories

* Remove tests