New Sonos S2 player provider

[marcelveldt]

Sonos S2 player provider, completely written from scratch (including the all new fully async aiosonos library), based on the new (S2-only) websockets API!

• Superfast, low latency, low overhead persistent connection to the speaker through websockets
• No more polling, no more continuous (xml) api calls
• Fully async so no more overhead from the executor
• No more dependency on 20 year old obscure xml libraries
• Superfast response times to commands
• Fully compatible with the S2 app

Discovery of players is entirely done based on mdns broadcasts.
Note that the new Sonos player provider only works for S2 generation Sonos devices.

For MA to still support S1 generation speakers, I've refactored the old provider into the Sonos S1 provider and optimized it for S1 generation devices (including fallback polling)