Publish transfer function for 1D channels

Feedback from @sebastien.petitdemange

For now it is not possible to publish a transfer function for 1D channels.

That's array of values of the X axis according to X index of the data.

That's fixed value which can be considered as static during the scan (basically that's a metadata), else, it have to be handled in another way.

Main use cases

• Energy axis for MCAs (many beamlines)
• Linear wavelength axis for spectrometers (ID24, ID27...)
• Log frequency axis for the flex (ID10) (the amount of point is not fixed between scan steps, so it's in the end not the same use case, i have created #2693 (closed))

Problematic

• How/where to publish the data?
  • Dedicated channel
  • Inside scan scan_info
  • Inside channel info
• How to write it in NX?
• How to display it in Flint?