Remove workaround for 5.3

Function is natively available with 5.4
OC8 and later requires PHP >= 5.4, so we can remove the check from the encryption app
translate labels properly
adding default key value pair for 'types'
adding new dependency for php version in apps info.xml
introduce dependency analyzer to take care of app dependencies
some more unit tests on xml info parser
display missing dependencies in the apps management page
adding supported databases
switch to different parsing implementation to get xml attributes properly handled
adjust dependency analyzer to use attributes properly
adding command dependency
fix an issue where the types tag holds an empty string
no nested xml tags on dependencies
update error message
Merge pull request #12610 from owncloud/remove_php_version_check

[encryption] remove check for PHP version
Merge pull request #12533 from owncloud/app-dependencies-php-version

App dependencies php version
Merge pull request #12609 from owncloud/remove-53-fixme

Remove workaround for 5.3
Add public api for mount configurations
Use the mount config api for files_external