Feature: #96614 - Automatic inclusion of page TSconfig of extensions 

See forge#96614

Description 

Extension authors can now put a file named Configuration/page.tsconfig in their extension folder.

This file is then recognized to load the contents as global page TSconfig for the whole TYPO3 installation during build-time. This is much more performant than the existing solution to use ExtensionManagementUtility::addPageTSConfig() in ext_localconf.php, which is added to $TYPO3_CONF_VARS[SYS][defaultPageTSconfig] during runtime.

Impact 

When a file is created, the page TSconfig is loaded automatically without a custom registration anymore, and cached within the Core caches, and more performant than the existing registration format.