Implement a Static Object Container
As work on #3583 showed, object creation takes a lot more time than desired. Especially autowiring is a good target for further work.
What would mostly solve the speed issues would be a static object container, i.e. automatically generated PHP code which contains all the wiring – hardcoded.
[+FEATURE] FLOW3 (Object): Implemented a static object container which is automatically built. It's essentially a hardcoded version of the autowired and configured object dependencies - just a lot faster. Many tests are still missing, but the version in this commit should be mostly functional. Addresses #3740 and resolves #2123.
[!!!][~API] FLOW3 (Object): Heavily refactored the Object Manager and its tests. The most important change is the removal of the Object Factory whose create() method is now located in the Object Manager. Furthermore, the getObject() method has been renamed to get() and a few minor important API functions within the Object Manager have been modified. This commit also contains a script which allows for semi automatically migrating existing code to the new API (see ./flow3 migrate objectmanagerusage). Resolves #6562
[~TASK] FLOW3 (Configuration): The Configuration Manager and its YAML source now doesn't depend on the YAML package anymore but refers to a YAML parser class within the FLOW3 package. Resolves #6564.