Migrating T2T to TF2

[branko-fathom]

My org is looking to migrate to TensorFlow 2.7.4 by the end of June in order to not lose TPU access in GCP. The current plan for our fork is to utilize the tensorflow.compat.v1 APIs (along with updating contrib imports to use tensorflow_addons and tf_slim) and tf.disable_v2_behavior(). Is this all that's required to get t2t working with TF2?