* implement the conformer
* format code style
* format code style
* reuse the TransformerEncoderLayer in the vision_transformer.py
* Modify variable name
* delete unused params
* Remove warning info in Conformer head since it already exists in
Conformer.
* Rename some variables
* Add unit tests
* Use `getattr` instead of `get_submodule`.
* Remove some useless layers
* Refactor conformer and add configs
* Update configs and add metafile.
* Fix unit tests
* Update README
Co-authored-by: mzr1996 <mzr1996@163.com>
Zhiliang Peng