Adapted memoization policies for graph (RasaHQ#9383)

* Adapted memoization policies for graph

* Not persisting config anymore for graph policy components

* adjusted unit testing for memoization graph component

* Removed max history hack in ted policy

* Making sure policy config is used for initializing featurizers if necessary

* Added policy priority to ted policy default config

* Simplified policy test suites

* Persisting policy by default when training

* Only carrying over max_history from policy to featurizer for MaxHistoryTrackerFeaturizers

* Turned load fail logging to warning from info

* Removed compatibility code for old policy component types

* Removed metadata and persist abstract methods from policy class

* Joined all memoization policy tests

* Fixed delorean code