DMserver: ability to read and change dispersion(and more) from client side.

[utkarshp1161]

Background: Parameters like changing dispersion is not yet supported in DMserver. Issue being unable to call it directly using python api of DigitalMicrograph.

As discussed this should be able to be done using hybrid(DM script and Python) scripts. Gerd suggested to add tags(like python dictionaries but in c) as returning variables back in hybrid scripts is not supported.

Reference: https://github.com/miile7/execdmscript

[utkarshp1161]

Update: Looks(based on discussion at mm2025) like the best way to achieve eels acquisition(and access to all the parameters and right processed spectrum) would be using hybrid scripts rather than python based acquisition.