Add extended SRMD.xsc for SL1

[jdsika]

The current srmd checker is only validating generic rules which do not check sensor model specific keywords. I would suggest to extend the .xsd checker for each sub-library and add those schema files top the overarching test-architecture repository:
https://github.com/openMSL/.github/blob/main/doc/osmp_test_architecture.md#srmd-validator

New sub-libraries could then see how this extension process works and the community of a specific SL can converge on the required keywords

[jdsika]

1. create a .xsd schema extension valid for all OpenMSL sub-libraries
2. define the process in the test architecture documentation
3. allow for SL specific extensions
4. research on how those extensions can be created (allow fileds which are not specifically defined)

[ClemensLinnhoff]

I will look into it.

[pmai]

I think the approach taken in https://journal.code4lib.org/articles/13546 should likely be taken into account, i.e. using Schematron rules embedded in an extended XML Schema. Supported by OxygenXML and, it seems, open source tools like https://github.com/TheLanguageArchive/SchemAnon ...

Benefit is that Schematron is better suited to the kind of fine grained rules likely needed for content validation.

That said, in the broader GAIA-X context maybe translation to RDF and checking with SHACL files is a better approach entirely...