[cob_twist_controller] refactor constraints/GPM code

[fmessmer]

• remove priority template: <typename PRIO = uint32_t> @ipa-fxm-cm
• separate and clearly name constraint builder/factory from actual constraints
• use *.cpp and create library instead of *_impl.h
• extract abstract GPM solver (i.e. just GPM formular) from actual GPM implementation (i.e. sum over constraint list)
• allow to use constraints with/without prediction, toggleable via parameter (could help with [cob_twist_controller] CollisionAvoidance constraint does not work with KinematicExtensions #64)

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• optional: remove dynamic reconfigurability for solver types @ipa-fxm-cm

@fmessmer FYI

[fmessmer]

@ipa-fxm-cm
I think we should keep the dynamic reconfigurability for the time being...so could you please focus on "remove priority template" first?

[bbrito]

I agree. At the moment for me at least dynamic reconfigure is really useful. But once we finish all this solvers and make them stable we can start removing it.

[fmessmer]

In https://github.com/ipa320/cob_control/pull/126 we started to debug #125, but did not pursue this any further....thus it has been closed unmerged...

[fmessmer]

getting rid of the priority template is not that easy....I started it in my branch, but I'm not able to compile it yet...

Problem is:
When trying to get rid of the priority template, the whole PriorityBase class actually is obsolete and could be removed leaving ConstraintBase as the top abstract class for constraints...
However, I then ran into issues with a templated typedef for ConstraintBase_t which is used all over the place...and I couldn't resolve it yet...