Fix initialization for TranslationalPosition and add more tests

[SebastianM-C]

Checklist

• Appropriate tests were added
• Any code changes were done in a way that does not break public API
• All documentation related to code changes were updated
• The new code follows the
  contributor guidelines, in particular the SciML Style Guide and
  COLPRAC.
• Any new documentation only uses public API

Additional context

The initializations produced by the TranslationalPosition components are very overconstrained. I think that there were some initialization workarounds that were needed in the past, but on more modern MTK versions these should no longer be needed.

One of the things that I removed is the equations that wereflange.s from higler level components shuch as the Spring and Damper. Is this breaking?

[baggepinnen]

I have no objections, the Translational and TranslationalPosition have historically had so many warts that I found them unusable, and instead added the TranslationalModelica library for use from Multibody.jl.

In the future, I say we remove both of those and use only TranslationalModelica (renamed to Translational)