Compatability with .slnx format

[MPapst]

Description

Parse and map the newly supported slnx file format for solution files.

Previously mentioned in #1375, but with .NET SDK 9.0.2x now officially supported.

Usage Example

• Should work in the same way as the current solution file parsing.
• Should be completely transparent for the developer

Alternative

No response

Could you help with a pull-request?

Yes

[Droppers]

This library provided by Microsoft could be used for that:

https://github.com/microsoft/vs-solutionpersistence

[MPapst]

I would like to add an parser.

Would you prefer manual parsing or adding the MS parser?
An additional package (if that is even possible, haven't looked up the architecture) or inline?