Feature: #89010 - Introduce Site Configuration for Distribution Packages

See forge#89010

Description

Distributions or site packages are designed to deliver a full blown TYPO3 instance with all necessary data and assets to have a functional installation after the package has been activated. The import of a distribution can now ship the config file (or many, if this is required).

Similar to assets, that are moved to fileadmin ready for use, site configurations are moved into the config folder.

Impact

Distributions can now ship their own site configuration files.

Example:

Into the distribution package Initialisation/Site folder, put a folder with the site identifier as name, containing the config.yaml. Each folder will be moved into the target position upon extension activation.

If a folder with the same name already exists, the file will not be overridden. In this case no change is made to the existing configuration.