feat: speed-controlled fans

[lorenz]

This implements the discovery side for speed-controlled fans. Here we no
longer need to emulate speed changes by changing modes and there is a
readily-usable onOff cluster for state. Fans now need to be either mode-
or speed-controlled, otherwise an assert is hit. No such fans currently
exist in the Z2M codebase and they cannot be reasonably controlled
anyways.

Co-dependent with Koenkk/zigbee-herdsman-converters#8188

[github-actions]

This pull request is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 7 days

[lorenz]

Not stale, depends on another PR.

[Koenkk]

@lorenz could you take a look at the failing CI?

[lorenz]

Most things are fixed, now it wants me to add test coverage for an assert statement, I'm not sure how I would even test that considering that an assert basically aborts the NodeJS runtime.

[Nerivec]

You can find plenty of examples in current tests, usually in that format:

expect(() => {
   // TODO
}).toThrow('The error message');

[lorenz]

Fixed it by removing the branch and using the assertion value.

[Koenkk]

Thanks!