Move issues related files into models/issues (#19931)

* Move access and repo permission to models/perm/access

* fix test

* fix git test

* Move functions sequence

* Some improvements per @KN4CK3R and @delvh

* Move issues related code to models/issues

* Move some issues related sub package

* Merge

* Fix test

* Fix test

* Fix test

* Fix test

* Rename some files

routers/api/v1/repo/patch.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"code.gitea.io/gitea/models"
+	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/modules/context"
 	"code.gitea.io/gitea/modules/git"
 	api "code.gitea.io/gitea/modules/structs"
@@ -78,7 +79,7 @@ func ApplyDiffPatch(ctx *context.APIContext) {
 	}
 
 	if !canWriteFiles(ctx, apiOpts.BranchName) {
-		ctx.Error(http.StatusInternalServerError, "ApplyPatch", models.ErrUserDoesNotHaveAccessToRepo{
+		ctx.Error(http.StatusInternalServerError, "ApplyPatch", repo_model.ErrUserDoesNotHaveAccessToRepo{
 			UserID:   ctx.Doer.ID,
 			RepoName: ctx.Repo.Repository.LowerName,
 		})