Snapcast support

**Describe the problem you have/What new integration you would like**
Integrating the following work with esphome: https://github.com/jorgenkraghjakobsen/snapclient

**Please describe your use case for this integration and alternatives you've tried:**
Create a free software, cheap sonos clone for multi-room audio.

**Additional context**
I would like to have a system that is as energy-efficient as possible, I think the esp32 might be suitable for this. Ideally, the workflow would be the following:

Materials needed:
1. ESP32
2. MA12070P or similar
3. Analog speakers
4. (battery if you want) power supply

Software needed: Snapcast server

Ideally, I would like the installation process to be as simple as soldering together the modules, specify it in the config, and flash, then have it pop in homeassistant.

A possible alternative would be to use separate bluetooth speakers. I am not sure how feasible this would be?

Start by reviewing the linked snapclient project and ESPHome's integration architecture; no project files or tests are named in the request. Define the required ESP32 audio workflow, configuration, flashing process, and Home Assistant discovery behavior before implementation can be considered done.

Written by the indexing model from the issue text.