Unroll transformation for TensorIterator (#1259)

Unroll transformation for TensorIterator (#1259)

* unroll ti transformation, lstm sequence ie, rnn sequence ie

* Update unroll ti transformation, added GRUSequenceIE op, fixed several ti e2e tests

* apply ngraph codestyle

* fix naming after unroll transformation

* Added default constructor for RNNCellBase, fix conversions

* copy runtime info

* added UnrollTI unit tests

* clean up, move sequence ops in a separate PR

* clean up, ngraph code style

* temporary disable ngraph reader unit tests for ti

* fix unit tests on windows

* naming: use name of tensor after unroll tensor iteration transformation

* apply transformations to tensor iterator body, separate pass for ti transformations, fix naming issue

* fix build

* remove TensorIterationTransformations pass

* fix includes

* resolve conflicts

* fix build: incorrect includes

* remove split/concat for single iteration of TI, update to opset4, unit tests

* use matcher pass instead of graph rewrite

* try to enable UnrollTI transformation for all plugins

* disable unrollTI transformation for cpu plugin

* resolve review comments, enable unit tests

* update transformation description

* fix unit tests

* update transformation pipeline

* clean up

* clean up

* resolve review comments