BruteFir integration

[bitlab]

@jijopujolo if you can find that reference back it would be very helpfull ?

I used now the bandwith calculations from https://www.audiorecording.me/parametric...s.html/amp, but those outcomes differs ~ 2x from the actual used bw of EqFa4p.

Anyway to ease use the configuration interface is now using Q instead of bw. It would be great to have more well-founded Q calculation.