OpenIPSL models

[hexaeder]

This PR starts adding OpenIPSL models.
Many OpenIPSL models are tested in a SMIB model. We can execute those test cases and export CSV files from them.
We reproduce the SMIB test case in PowerDynamics so we can directly compare to reference. This PR implemnts the

• SMIB "testharness" in power dynamics
• implements a script which automaticially creats the csv reference files for a testcase
• implements the PSSE.GENCLS model and tests it against reference

It also includes a markdown file explaining the process which can be feed to AI agents to hopefully partially automate the process.

Machines

• GENCLS
• GENROU
• GENROE
• GENSAL
• GENSAE

Exciters

• IEEET1
• ESST4B
• ESST1A - needed for testcase of IEEEST
• EXST1
• SCRX

Govenors

• IEEEG1
• GGOV1 - well, its complicated. I think the OpenIPSL model is slightly wrong and the initialisation is at its limits. So implemented but not ready for use and not fully tested
• HYGOV - also a bit complicated (initialization point not unique)

PSS

• IEEEST -> needed in IEEE39 files from Texas AMU

[hexaeder]

We have some problems with the doc layout. I linked the references images in the docstring of the models:

Validated against the OpenIPSL SMIB testcase
[`Tests.Machines.PSSE.GENROU`](https://github.com/OpenIPSL/OpenIPSL/blob/fe8aa5c/OpenIPSL/Tests/Machines/PSSE/GENROU.mo).
See [validation plot](../assets/OpenIPSL_valid/GENROU.png) generated by automatic validation script in `/test/OpenIPSL_test`.

however, this is not registered as a correct relative link ../assets/OpenIPSL_valid/GENROU.png in a docstring, because it only makes sense once the docstring is spliced into the ComponentLibrary.html file.
I'm gonna merge anyway. This will result in a red cross in doc ci for now, however since i am per default rebuild the docs nonstrict (disabled linkcheck) for deployment we still get deployed docs. I'll figure out a better solution later to get the green badge back. In the build document the links actually work, its just that they don't satisfy the strict interlink checks.