When running with a user database backend on large installations the
cache can grow to significant sizes. This can be especially problematic
when running big cron/repair jobs.

* Move out of legacy folder
* Move to proper namespace
* Fix calling code

* Fix code
* Fix tests

Catching the login exception and returning false (login failed). Makes
the OCS API properly return data instead of printing the exception page.

Conflicting PR probabaly caused this

As discussed we move all old style classes (OC_FOO_BAR) to legacy.
Then from there we can evaluate the need to convert them back or if they
can be fully deprecated/deleted.

This makes sure that even if a NFD file name exists, it is found by the
storage and will be visible to higher layers. Even though the file will
be discarded anyway there, it gives the scanner a chance to display a
warning at least.

* \OC\OCSClient
* \OC\Preview
* \OC\PreviewManager
* \OC\Repair
* \OC\RepairException
* \OC\Search
* \OC\ServerContainer
* \OC\ServerNotAvailableException
* \OC\ServiceUnavailableException
* \OC\Setup
* \OC\Streamer
* \OC\SubAdmin
* \OC\SystemConfig
* \OC\TagManager
* \OC\Tags
* \OC\TempManager
* \OC\TemplateLayout
* \OC\URLGenerator
* \OC\Updater

* \OC\DateTimeFormatter
* \OC\DateTimeZone
* \OC\ForbiddenException
* \OC\HTTPHelper
* \OC\HintException
* \OC\LargeFileHelper
* \OC\Log
* \OC\NaturalSort
* \OC\NavigationManager
* \OC\NeedsUpdateException
* \OC\NotSquareException

* \OC\ActivityManager
* \OC\AllConfig
* \OC\AppConfig
* \OC\AppHelper
* \OC\Avatar
* \OC\AvatarManager
* \OC\CapabilitiesManager
* \OC\Config
* \OC\ContactsManager
* \OC\DatabaseException
* \OC\DatabaseSetupException

simplify comparison

remove additional null

fix off by 1 error