Stabilisation during walking

[texhnolyze]

If it is needed, because of backlash issues in the legs we want to do active stabilization during walking.

Wait for results of: bit-bots/bitbots_hardware#42

[texhnolyze]

We should take a look at the following PR: bit-bots/bitbots_motion#387
and potentially take it as a basis for this issue.

[jgueldenstein]

@Flova would you say that this is solved "enough" by the imu phase reset? What other stabilization techniques did you want to try ?

[Flova]

We currently do the phase reset and have a pid controller moving the trunk offset (translation) iirc. That works pretty well.