Actuator behaviour emulation

[bartboogmans]

Implement thruster states that are configurable

E.g. rate limited:
state1 = x_ref (input)
state2 = x_actual (output, used for calculating responses, follows x_ref with limited rate)

with a set rate limit based on actuator speed.

[bartboogmans]

Another idea is to also similarly publish telemetry as far as we can sensibly emulate.

e.g. motor responses, magnetometer values, etc. etc.