Bring in NOMAD examples

[lukaspie]

• NOMAD entry point for MPES example
• NOMAD integration test
• bring in example data
• update docs and README

[lukaspie]

@rettigl this should be ready. The tests are failing here because they don't install the specific pynxtools branch. But as you can see in FAIRmat-NFDI/pynxtools#448, the plugin tests work. So we can just merge that one first and re-run the tests here.

[rettigl]

The structure looks okay, but the actual example data don't seem to be the correct ones. Please take this as source:
https://gitlab.mpcdf.mpg.de/nomad-lab/north/mpes/-/tree/main/example?ref_type=heads
I will test again if that works with most recent everything.
For future compatibility, please add a version limit to sed-processor <1.0.0, as we want to release some breaking changes with v1 there soon, which will require a new config format.
What the tests do I don't really understand.

[lukaspie]

For future compatibility, please add a version limit to sed-processor <1.0.0, as we want to release some breaking changes with v1 there soon, which will require a new config format.

I added it. sed-processor was not part of the requirements in pyproject.toml so far, but I suppose we should add all the tools that the examples are running. Is there anything else to add? I guess pyARPES?

Also, in E1, we are downloading the example data again with curl? Is this intentional (i.e., when not used in nomad directly)? If so, we should re-add it in E4 as well.

[rettigl]

Seems okay now.