Fixed mtime reading from OpenStack API

Use the correct resolve method to resolve file storage (x-sendfile)

When detecting whether the file to be downloaded is on external storage,
the correct path needs to be used.

It turns out that \OC\Files\View is needed to resolve the path correctly
relative to the user's home.

The API seems to return floating point values, which prevents
the hasUpdated() check to work and causes the scanner to rescan
everything every time.

css files are not to be routed through index.php anymore

Miscellaneous text fixes for core apps

Fix undefined index warning in router

Fix merging of external storage configurations

Pretty print mount.json when possible

Merging of configurations is whenever the same config is available for
multiple users/groups, in which case the config is considered as a
single one by the UI, and shows multiple users/groups selected.

Fixed merging logic to make sure that class, mount point and options are
the same before merging them.

Fixed merging to work correctly when the same mount point path is used
for separate users and configs. These are now correctly shows in the UI
as separate entries.

Added PostgreSQL version warning on upgrade

Routing performance

Recursive mkdir fixes #7047

Manually triger the filecache update hooks before any other hook

Allow re-using already known fileinfo when calculating folder sizes

Also replace console.time/timeEnd when not in DEBUG mode

Log last cron execution

Fix public upload to not close session when encryption is on

idn have to be converted before being used

The encryption app needs to create keys when uploading files, so the
session needs to be kept open in such case.