Support asyncio with AsyncInferenceClient (#1524)
* prepare for async
* more stuff
* comments
* add aiohttp to deps
* prepare script to generate AsyncInferenceClient
* some progress
* more progress
* make methods async
* await post calls
* remove examples in AsyncClient
* working generating script?
* make async
* explicit regexes
* working AsyncInferenceClient
* moving further
* closer to a solution
* more explicit?
* fix typing
* fix tests
* fix tests for real
* Examples in async client
* adapt async text generation code
* better handling of errors
* first async tests
* fix tests for python3.7
* add sentence_similarity tests
* reference
* docs
* fix setup.py
* docs
* fix styling
* fix tests
* fix zero-shot task
* fix zero class
* Move _async_client.py to a _generated/ folder
* add copyright to tests
* fix imports
* fix import
* fix async text_generation return type when stream=True
* test async methods signatures
