Adapt MX2 docs for mapping features added in #16749

[klassenserver7b]

See mapping PR in main repo

[JoergAtGithub]

The mapping documentation was converted from .rst format to .md format. Please apply your changes to the file in the new format to resolve the conflicts.

[klassenserver7b]

The mapping documentation was converted from .rst format to .md format. Please apply your changes to the file in the new format to resolve the conflicts.

Should be all valid markdown now
How do you want images to be done? Because they are broken in all autoconverted markdown files. Also, the added / changed in VERSION isn't right yet.

I guess it could be possible to use standard Markdown ![ALT](PATH) way depending on how the build chain handles it and resolves the relative paths to actual image urls

[JoergAtGithub]

The images in the manual generated by Sphynx from the markdown files appear exactly as in the original .rst based version. This is what matters.

[klassenserver7b]

Should be alright now. I know it's a bit of a troll sentence but "my local builds look as intended"

[JoergAtGithub]

Please fix the build check errors

[klassenserver7b]

Please fix the build check errors

I fixed everything related to my docs. The remaining issues seem to originate from other parts of the documentation that weren't touched by this PR.