decimate the gyro window locally
configure rate loop buffer based on AP_INERTIALSENSOR_FAST_SAMPLE_WINDOW_ENABLED
allow backends to be updated from rate thread
output debug error if rate loop buffer overruns
add support for updating filter parameters independently of propagating samples
add rate loop config abstraction that allows code to be elided on non-copter builds
must be using harmonic notch to use rate thread
mediate fast rate loop buffer using mutex and binary semaphore
ensure gyro samples are used when the rate loop buffer isn't
Co-Authored-By: Andrew Tridgell <andrew@tridgell.net>