Reduce usage of db.DefaultContext (#27073)

Part of #27065

This reduces the usage of `db.DefaultContext`. I think I've got enough
files for the first PR. When this is merged, I will continue working on
this.

Considering how many files this PR affect, I hope it won't take to long
to merge, so I don't end up in the merge conflict hell.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/api/v1/repo/fork.go

@@ -55,7 +55,7 @@ func ListForks(ctx *context.APIContext) {
 	//   "404":
 	//     "$ref": "#/responses/notFound"
 
-	forks, err := repo_model.GetForks(ctx.Repo.Repository, utils.GetListOptions(ctx))
+	forks, err := repo_model.GetForks(ctx, ctx.Repo.Repository, utils.GetListOptions(ctx))
 	if err != nil {
 		ctx.Error(http.StatusInternalServerError, "GetForks", err)
 		return