add NXTransformations class and utils
flip_uddataset by standard NXTranslations -> for the large part of this pr remove it but it would be better if we can keep some compatibility for some time
update rotation_angle, x_translation, y_translation, z_translation ?-> lets go one step at the time
add an example on how to add Transformation to an NXdetector from a script (and limitations)
when dump to disk; for the Transformation without dependencies add dependence on gravity
integrate to nabu-> nabu#418 (closed)
integrate to tomwer-> tomwer#967
Today NXtomo documentation does not present any link to
NXsample does and recommand to use them. Which is confusing for the less.
Anyway for tomography
rotation_angle are convenient to have and we don't want to remove them.
rotation_angle is even mandatory.
So what could be done is to generate
NXtransformations group but based from other dataset values. This would prevent any conflict and make it more 'nexus' compliant. Else we keep this to the NXdetector which is necessary to store 'flip' l/r and u/d information