always specify limit, except you do like questionable surprises, part 2

Moved to files_sharing
Added more capabilities.
Tried to order to capabilities more OO style

`\OCA\Files\Helper::buildFileStorageStatistics` might throw an exception from `OC_Helper::getStorageInfo`, previously this lead to a uncatched exception being thrown when invoking this methods.

This was user triggable by for example calling `/index.php/apps/files/ajax/delete.php` with a not existing dir (for example `dir=asdf/../&allfiles=true`)

This fixes #13673.
It now lists link sharing, passwords enforced, and if public uploads are
allowed.

Without CSRF check this file might be tricked into requesting itself which would result in an endless loop and thus potentially ending in a Denial of Service.

Also shows a notification in case an error occured on updating the tags

get correct user for paths to the trash bin, needed for remote shares if the size of of trash gets calculated