Extend decoder types to FSK, that are currently available only for OOK #3409
Description
For OOK, many predefined bit decoding methods are available: OOK_PULSE_PCM, OOK_PULSE_RZ, OOK_PULSE_DMC, etc. But for FSK, only three methods are defined (PCM, PWM, Manchester with hardcoded zero bit). However, many devices use various forms of Manchester encoding, but FSK_MC_ZEROBIT is not suitable for all of them. Because of this, many decoders are forced to get a raw stream of demodulated bits and then call the appropriate decoding method (already implemented in the core).
Similarly, to define a flex decoder, only three decoding methods are available for FSK. But is not possible for a flex decoder to call an appropriate decoder from the core. So it is not possible to define a flex decoder for such data formats now.
It seems to me that it makes sense to make the full set of already implemented bit decoders available both in r_device and for a flex decoder definition.
Moreover, it makes sense to specify the modulation (OOK/PSK) independently from the decoding method (PCM/PWM/PPM/Manchester, etc.). If support of new modulation/decoding methods will be added in the future, they won't interfere with each other.