Provide API for developers to adjust registered Extbase plugins
Right now it is only possible to re configure a plugin by calling \TYPO3\CMS\Extbase\Utility\ExtensionUtility::configurePlugin a 2nd time.
Also in order to change the default Controller-Action-Combination one needs to unset $GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['extbase']['extensions']['ExtensionName']['plugins']['PluginName'] upfront.
That is very clunky and a clean API to configure and reconfigure a plugin would be much better.
Also Extbase could use a clean API in order to retrieve those info, instead of accessing a TYPO3_CONF_VARS array.
The new API should also only be intended for use within ext_localconf.php, not during runtime.