TYPO3 Core

Instead of reading the composer.json / ext_emconf.php
of extensions at runtime just to retrieve the extension title,
use the existing package meta data API to store and retrieve this
information.

Add a place in composer.json extra section to store an optional title
of an extension and use this to populate the meta data, but
add fallback handling for Composer mode as well to read ext_emconf.php
in case the newly introduced composer.json property is not set
to avoid a change in behaviour in extension manager.