Cleanup libf3d options / cli options names

[mwestphal]

With the upcoming release of F3D 3.0, take that opportunity to cleanup all options names.

related to: #918

[mwestphal]

[mwestphal]

the interactor.axis option that toggles the little axes widget in the corner may be better as ui.axes to match the other overlays (ui.cheatsheet, ui.filename, ...)?

[mwestphal]

Here are my suggestions:

progress -> loading-progress
trackball -> interaction-trackball
cells -> coloring-by-cells
range -> coloring-range
bar -> coloring-scalar-bar
inverse -> volume-inverse
samples -> raytracing-samples
denoise -> raytracing-denoise
ref -> reference
ref-threshold -> reference-threshold