* Store avatars outside of the home

Inside a hidden "metadata-avatars" folder.
Doesn't require home FS setup

* Fix it

* Store avatars in e.g. a/d/admin, using md5 on non alphanumeric characters and refactor tests

* Always do an md5 of the user name

* Update Util.php

* Adjust avatar migration version check

* Fix LazyRoot folder to properly return get() value

* Fix avatar migration with the new folder

* Don't fail move avatar step if user has no home at all

* Fix use statement for IRootFolder