Disable Stars config option (#14653)

* Add config option to disable stars

* Replace "stars" with watched in user profile

* Add documentation

modules/setting/repository.go

@@ -43,6 +43,7 @@ var (
 		PrefixArchiveFiles                      bool
 		DisableMirrors                          bool
 		DisableMigrations                       bool
+		DisableStars                            bool `ini:"DISABLE_STARS"`
 		DefaultBranch                           string
 		AllowAdoptionOfUnadoptedRepositories    bool
 		AllowDeleteOfUnadoptedRepositories      bool
@@ -154,6 +155,7 @@ var (
 		PrefixArchiveFiles:                      true,
 		DisableMirrors:                          false,
 		DisableMigrations:                       false,
+		DisableStars:                            false,
 		DefaultBranch:                           "master",
 
 		// Repository editor settings