Decouple audio capture from projectM wrapper + GHA fixes

[kblaschke]

This changeset removes the direct projectM dependency in the audio capture implementations, using notifications instead.

This provides a few advantages:

• No need to pass in/know the projectM handle or use projectM API functions in the audio capture classes.
• Since a notification can have multiple subscribers, which are notified in sequence, this allows to pass captured audio to multiple projectM instances without the audio capture driver needing to know the number of recipients (can be >=0).
• Audio data is now transferred to a buffer in the ProjectMWrapper class in a thread-safe manner, removing any possible race conditions.
• This change allows to have more than one projectM instance at the same time, e.g. to implement a multi-window mode or show a small UI window with an animated preset preview.

The audio capture driver can still capture asynchronously in a separate thread or read the audio data when its FillBuffer() method is called. Audio data is transferred to the projectM instance immediately before the frame render function is called.

Edit: merged the build fixed to master separately to re-enable build checks in other branches.