Restrict permission check on repositories and fix some problems (#5314)

* 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

models/fixtures/team_unit.yml

@@ -207,3 +207,18 @@
   id: 42
   team_id: 6
   type: 7
+
+-
+  id: 43
+  team_id: 7
+  type: 2 # issues
+
+-
+  id: 44
+  team_id: 8
+  type: 2 # issues
+
+-
+  id: 45
+  team_id: 9
+  type: 1 # code