Sprint22 microstructure

[mkuehbach]

No description provided.

[lukaspie]

Only reviewed changes to NXcoordinate_system_set so far.

I support having the conventions liker rotation_handedness, rotation_convention, euler_angle_conventions, and so on in NXcoordinate_system_set (though maybe can be different for different coordinate systems, not sure).

I am of two minds w.r.t. explictily defining different coordinate systems within the base class NXcoordinate_system_set. Essentially, this just makes sure all appdefs use the same name if they are talking about a coordinate system of e..g. the sample. This may be helpful. That being said, the coordinate system descriptions here are 1) too specific still (mostly to EM), and 2) oftentimes just repeating what is already in the NXcoordinate_system base class, so we can delete most of the fields in these named CSs.

[lukaspie]

This looks much cleaner already. I think you could clean up even more by stating the assumptions directly in the docs of the respective classes and adding a sentence that people who use different assumptions must explicitly state these.

[mkuehbach]

All issues from @lukaspie were addressed.

[mkuehbach]

Neither conflicts nor revision requests currently block this PR from becoming merged into fairmat. However, as it was discussed for #270 development should continue despite vacation.

Therefore, this draft PR will be closed and instead sprint22_microstructure merged into sprint23_em_v3.
This enables to address merge conflicts between these two feature development activities to compose
one update for the EM line of features in NOMAD without currently breaking code without taking the
team the possibility to make revisions.