mcxtrace: SOLEIL: add Nanoscopium BL

[farhi]

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This PR adds the SOLEIL Nanoscopium BL (from Clotilde Gaudry)
Compiles OK.

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PR Checklist for contributing to McStas/McXtrace

For a coherent and useful contribution to McStas/McXtrace, please fill in relevant parts of the checklist:

• My contribution includes a new instrument file

  • I have used the mcdoc utility and rendered a reasonable documentation page for the instrument (please attach as screenshot in comments!)
  • I have ensured that basic use of the instrument is OK (e.g. it compiles?)
  • ... and provided reasonable default parameters in that instrument that produce reasonable output
  • ... and maybe even added a %Example: line to describe expected behaviour
  • I have used the mcrun --c-lint "linter" and followed advice to remove most / all warnings that are raised
  • My new instrument is added within the examples hierarchy in a folder in the style of examples/ESS/New_stuff/New_stuff.instr
  • My new instrument has a new, unique filename, not clashing with existing example instruments
  • My new instrument requires a data/input file. If the datafile is specific for my instrument I have left it in the same example folder, but if general use I have placed it in the global data folder.

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[willend]

[willend]

The instrument only misses a %Example line with a test target

[willend]

@farhi test value way off SOLEIL_NANOSCOPIUM : 12.04 [val: 1.54292e+18 / 195278000.0 = 790114605844 %] <--- BIG DISCREPANCY??