Feature: #89894 - Separate system extensions from 3rd-party extensions visually

Description

The Extension Manager in TYPO3 allows backend users to list, activate, deactivate, configure and possibly add/remove extensions from the system. When using the Extension Manager, backend users work with either core extensions (system extensions) or 3rd-party extensions, depending on their task.

The extension list shown in the Extension Manager can now be filtered by certain extension types (system and 3rd-party extensions).

Impact

A limited list of extensions, either system or 3rd-party extensions, makes it easier for backend users to find the extension they intend to work with and/or to get a quick overview which extensions are currently installed (e.g. 3rd-party extensions). This improves the usability of the backend for integrators/administrators.