tf2 estimator and training strategies

[davidsebfischer]

• train_sequence cannot be defined here but has to be used as defined in models/base/estimator.py
  

  batchglm/batchglm/train/tf2/base_glm/estimator.py

  Line 64 in 8f025e2

  def train_sequence(self, training_strategy: []):

• tf2 training strategies have to be adapted as discussed

[picciama]

train_sequence deleted
trainingStrategies.py deleted and integrated into model/estimator.
All changes within train/tf2.
@davidsebfischer If you checked whether your train_sequence method is working with our train method already, we are fine, otherwise I need to check that before we can close here.
train_sequence calls train multiple times, if more than one optimizer is given. However, each time train is executed, a new model is created again in our case. So this isn't yet working, instead, the training will start from scratch for each given optimizer.
Please tell me, if I need to fix this before closing here.

[davidsebfischer]

Please check that the new global train_sequence works for you, then close here.

You can close this even if train sequence restarts every time but open a new issue for the train sequence please.

[picciama]

train_sequence is working fine now. We might need to include additional information into th Enums of training_strategies.py in the future.