Feature request : async client

[nipil]

Would it be possible to provide an async/await interface ?

Reasoning :

• the client requests package which is sync only, and HTTP/1.1 only
• to go async, you must wrap each client call in to_thread or run_in_executor

Proposal :

• provide an async ovh client producing awaitables
• use either httpx or aiohttp package to provide async HTTP requests
• using httpx instead of aiohttp would enable HTTP/2

PS: i have seen in #128 that using non well-known libs was not desirable for the project.
In this regard, I do not know if you would consider httpx or aiohttp as well established.