Add API for manipulating Git hooks (#6436)

* Add API for manipulating Git hooks

Signed-off-by: Segev Finer <segev@codeocean.com>

* Replace code.gitea.io/sdk with PR branch temporarily for CI

* Switch back to code.gitea.io/sdk@master

* Return 403 instead of 404 on no permission to edit hooks in API

* Add tests for Git hooks API

* Update models/repo_list_test.go

Co-Authored-By: segevfiner <segev208@gmail.com>

* Update models/repo_list_test.go

Co-Authored-By: segevfiner <segev208@gmail.com>

* empty line

modules/context/api.go

@@ -125,10 +125,10 @@ func APIContexter() macaron.Handler {
 }
 
 // ReferencesGitRepo injects the GitRepo into the Context
-func ReferencesGitRepo() macaron.Handler {
+func ReferencesGitRepo(allowEmpty bool) macaron.Handler {
 	return func(ctx *APIContext) {
 		// Empty repository does not have reference information.
-		if ctx.Repo.Repository.IsEmpty {
+		if !allowEmpty && ctx.Repo.Repository.IsEmpty {
 			return
 		}