Improve handling of Public API files when creating new projects

[aaronpowell]

We have to add two files when you create a new integration, a PublicAPI.shipped.txt and PublicAPI.unshipped.txt. These don't get created using the template and as a result, you end up with a build error initially.

There needs to be a better workflow around this on creating a new project.

[aaronpowell]

@Alirexaa - first step is I'll review how the docs are related to the contributing guide

[github-actions]

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[Alirexaa]

/stale-extend

[aaronpowell]

Aspire has dropped these files and is using a new approach for 9.1 - microsoft/aspire#7369

Wonder if we could look to adopt that too.

[aaronpowell]

https://github.com/dotnet/sdk/tree/main/src/Compatibility/GenAPI is the tool they are using.

[Alirexaa]

I will take a look.