Add GetDevicePublicKey

[aromaa]

Description

Motivation and Context

• Following Add GetDevicePublicKey System.Net#265

How Has This Been Tested?

Screenshots

Types of changes

• Improvement (non-breaking change that improves a feature, code or algorithm)
• Bug fix (non-breaking change which fixes an issue with code or algorithm)
• New feature (non-breaking change which adds functionality to code)
• Breaking change (fix or feature that would cause existing functionality to change)
• Config and build (change in the configuration and build system, has no impact on code or features)
• Dev Containers (changes related with Dev Containers, has no impact on code or features)
• Dependencies (update dependencies and changes associated, has no impact on code or features)
• Documentation (changes or updates in the documentation, has no impact on code or features)

Checklist

• My code follows the code style of this project (only if there are changes in source code).
• My changes require an update to the documentation (there are changes that require the docs website to be updated).
• I have updated the documentation accordingly (the changes require an update on the docs in this repo).
• I have read the CONTRIBUTING document.
• I have tested everything locally and all new and existing tests passed (only if there are changes in source code).

[aromaa]

Okay, I somehow did something wrong while rebasing this to fix the force push conflict and messed up the whole commit history and lost my own while at it. sigh Anyways, fixed it.

[networkfusion]

@aromaa Is this PR still valid given all the changes?

[aromaa]

This needs a bit updating to stub the new platforms and a bit of updating. I'm planning to do that in the future as I will be needing to update my devices soon for the new Azure certificate so the branch will be up to date after that.

[aromaa]

Actually there wasn't much else to do as the new platforms are already falling back to the existing stubs. Fixed few copy & paste mistakes. Still seems to work just fine on my ESP32.