[TASK] #46 Implement extensionapi for TYPO3 CMS >= 6.0
[TASK] refactor ExtensionApiService class

* provide an ExtensionApiServiceInterface and
* two concrete implementations for 4.5 and > 6.0.0
* use DependencyInjection to choose the right implementation
[!!!][TASK] enforce usage of CommandController, if available

* do not provide the "old style" "coreapi" commands in > 4.6
[FEATURE] Add extensionapi info,configure and updatelist

* Tested in TYPO3_6-2-0beta1

Related: #39, #46, #47