Clarify path param naming (#32969)

In history (from some legacy frameworks), both `:name` and `name` are
supported as path path name, `:name` is an alias to `name`.

To make code consistent, now we should only use `name` but not `:name`.

Also added panic check in related functions to make sure the name won't
be abused in case some downstreams still use them.

routers/api/v1/org/org.go

@@ -131,7 +131,7 @@ func GetUserOrgsPermissions(ctx *context.APIContext) {
 	//     "$ref": "#/responses/notFound"
 
 	var o *user_model.User
-	if o = user.GetUserByParamsName(ctx, ":org"); o == nil {
+	if o = user.GetUserByPathParam(ctx, "org"); o == nil {
 		return
 	}