user: remove make local feature

we discussed a bit on what this does and it's confusing as it stands:

* Use case of this is lost in the realms of time
* Possible guess by is that it was to move users of different Cloudron to a central cloudron
* Currently, the design is a bit flawed because the make user local button doesn’t pin the user. The state is lost in next synchronization.
* Maybe, one should use export/import user for this use case
* Let’s disable this button for now, feature is not complete.

dashboard/src/js/client.js

@@ -2365,15 +2365,6 @@ angular.module('Application').service('Client', ['$http', '$interval', '$timeout
         });
     };
 
-    Client.prototype.makeUserLocal = function (userId, callback) {
-        post('/api/v1/users/' + userId + '/make_local', {}, null, function (error, data, status) {
-            if (error) return callback(error);
-            if (status !== 204) return callback(new ClientError(status, data));
-
-            callback(null);
-        });
-    };
-
     Client.prototype.changePassword = function (currentPassword, newPassword, callback) {
         var data = {
             password: currentPassword,