Investigate AOT compilation (for .NET 7)

[gfoidl]

Output is just the binary, so

• "curl"-install possible instead of installing the .NET tool
• independence of installed .NET SDKs (cf. .NET 6 compatibility #88, add support for .NET 7 #113)
• maybe a deb-package can be created, so installation is just apt install trx2junit

Just did a quick try to see if it works. For win-x64 the binary has ~10 MB and tests pass.