This somehow blocked the "Users" UI for me when having a lot of users. - Shouldn't hurt here.

This commit..
* doesn't check if a local or uploaded file is square to give a user the option to crop square images
* caches uploaded images to an initial temporary file (needed to fix orientation)
* fixes orientation based on exif data
* works for encrypted local images as well

Fix #4876

Sanitize displayname, respect data @ $element, fix routename, clean after cropping, updateAvatar with displayname