dont use post file upload for cover uploads
check cover upload file size against new setting
store cover uploads in profile folder
use `uid-profilecover` filename for cover uploads
Also added a number of fixes for mobile enhancements, such
as serving a manifest.json file for Android devices, and
serving proper link tags for all uploaded touch icons.
This commit also creates a new template helper for link tags.
1. filename cannot contain ':' (at least on windows), nodebb crashes with such filename
2. lwip cannot define image type without file extension
Also added image extension check to prevent security issues
barisusakli
Julian Lam
psychobunny
APXEOLOG