CoEx support (only works on ESP32-C3 for now), Refactoring

[bjoernQ]

This PR is huge (sorry) and probably doesn't make sense to read line by line - most important thing is it doesn't make things worse.

This

• reorganizes code to have BTLE and WiFi more separated, maybe makes adding support for additional chips easier (probably more refactoring needed)
• introduces two new feature flags to enable ble or wifi - one (or both) features need to be selected to build
• adds coex support - however it is only working on ESP32-C3 currently
  • since the PR is already huge it makes sense to get this in and look into ESP32 coex later
• changes the task switching on ESP32 to be much faster

Closes #50 for now

[jessebraham]

Sorry for taking so long to get to this! I didn't really do a proper code review (there's just too much, don't have the time right now) but it seems to be mostly working on my end. The existing examples for the ESP32 still work, and the ESP32-C3's examples are working... mostly.

For whatever reason, the Wi-Fi and CoEx examples get to this point and just hang:

Lets connect
Lets send
Lets receive

Testing with my mobile hotspot these examples both work again so it's just more network weirdness on my end, but this likely indicates there is some other underlying issue (like the last time we experienced this).

[bjoernQ]

Thanks a lot! I guess the examples are just quite bad and sometimes fail. Will have a look at that while working on the next task