The codepath for generating the favicons iterates through subnodes and if one of those nodes is unavailable is throwing a 503 exception. Since these favicons don't have any use except of "making a tool for developers looking nicer" I consider it feasible to remove them.

This improves the OCA.Files.FileActions class to support passing a
"render" function in the action object.

The default function "_defaultRenderFunction" is used by default and
renders actions in the usual actions container.

Moved "Rename" and "Delete" to custom render functions.

Fixes the OCS capability API at /ocs/v1.php/cloud/capabilities

Added namespaces so that JSDoc can find them.
Fixed a few warnings.
Improved some comments.

Added addTranslations and fixed de.js file

Fixed de.js to use OC.L10N.register() and use to correct expected
format.

Added JS unit tests for OC.L10N class

Include translations JS script for all apps

It's only reasonable to have proper type hinting here which might even help us to catch bugs.

Potentially fixes https://github.com/owncloud/core/issues/11742