[CPU] Support nested internal states

[maxnick]

Details:

This patch contains all the necessary changes to support internal states in the composite nodes (i.e. If, Loop, TensorIterator operations). Main changes:

1. Move the internal states registry to the graph context, so that all the nested internal states become accessible on the infer request level.
2. Move the state assing/commit actions to the node execute level, so that Loop and TensorIterator ops are automatically supported.

Tickets:

• CVS-134470

[maxnick]

@EgorDuplensky, could you please review?

[maxnick]

@EgorDuplensky , thank you!!!