FRQ: general distribution evaluate-class

[kay-ro]

Proposed new feature or change:

Additionally to evaluate.VelDist, LDDist and others, sometimes it is necessary to get the distribution function of different observables. One example is angular momentum which might be compared to a Maxwell-Boltzmann distribution. Others might be orientation distribution,...

• write general class evaluate.Dist
• allow for extra averaging functions (i.e. np.linalg.norm(...)/...)
• allow for logbins
• name in distobject.save(..., name="...")
• write examples in docstring also for saving!
• default name of class only "dist"
• write test