Support signing .rdp files

[kapsiR]

Is your feature request related to a problem? Please describe.
Since dealing with .rdp files is getting more strict in terms of security, it would be helpful to be able to sign these files too. (https://learn.microsoft.com/en-us/windows-server/remote/remote-desktop-services/remotepc/understanding-security-warnings)

Describe the solution you'd like
Be able to sign .rdp files too

Describe alternatives you've considered
There is a signing tool for RDP files, but this doesn't work with Trusted Signing or Key Vault. (https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/rdpsign)

Additional context
0.9.1-beta.26179.1+21990c8ec7ace15c7dcf334de241016627380ac0

[AkrosIT]

It is very disappointing that Microsoft has not supported the signing of RDP files
since the first version, given that Microsoft RDP is repeatedly the target of massive attacks.

[hangy]

I hacked up this tool last night. Based on NullOps.RdpSigner, it uses RSAKeyVaultProvider to sign RDP files.
I wonder if it could be interesting to publish the library on NuGet and integrate it here to have one tool for everything.

[kartheekp-ms]

Team Triage: We are willing to accept contributions for this feature request if the code changes are minimal (uses existing Windows APIs) and have test coverage.

[XVII]

@hangy , would be so nice to have this all in one tool!

Submitted a PR to the c# impl to fix some minor bugs.