Improve UI of external storage configuration

 * Highlight fields that need to be filled
 * Remove (required) and (optional) strings where possible
 * Focus first configuration field when creating new external storage
 * Add ability to force external storage re-check
 * Various jQuery improvements
 * Prevent wrapping of checkboxes in configuration
Merge pull request #10428 from owncloud/files_external_better_config

Improve external storage configuration UI
[tx-robot] updated from transifex
Add optional user ID parameter for getUseFolder
Use public api for getting l10n
Also extend public server interface
Merge pull request #10766 from owncloud/getUserFolder

Add optional user ID parameter for getUseFolder
Merge pull request #10768 from owncloud/l10n-use-public

Use public api for getting l10n
Move ajax calls in versions app to OCS API calls

Added OCS API calls for the versions app and make the JS side use them