[Core] refactor transformers 2d into multiple init variants. (#7491)
* refactor transformers 2d into multiple legacy variants.
* fix: init.
* fix recursive init.
* add inits.
* make transformer block creation more modular.
* complete refactor.
* remove forward
* debug
* remove legacy blocks and refactor within the module itself.
* remove print
* guard caption projection
* remove fetcher.
* reduce the number of args.
* fix: norm_type
* group variables that are shared.
* remove _get_transformer_blocks
* harmonize the init function signatures.
* transformer_blocks to common
* repeat .