Move ServiceBus extension to Azure SDK repo

[JoshLove-msft]

#17560
Moving the extensions from https://github.com/Azure/azure-functions-servicebus-extension with minimal changes necessary to compile and have tests passed. This will be helpful as a reference for future changes as we migrate to use the Track 2 library.

Notable issues that should be converted to GH issues:

• signing the sign.snk did not work as there was no private key, so I'm using the SDK repo snk - [WebJobs/ServiceBus] Update to use sign.snk once we get private key #17958
• TestCommon package did not support net461 so I updated the RequiredTargetFrameworks for the test project to just be netcoreapp2.1 - [WebJobs/ServiceBus] Restore RequiredTargetFrameworks to default for test project #17959

[pakrym]

Should we delete the snk file if we are not using it?

[jsquire]

My approval is based on the understanding that we're moving over existing assets; I've only reviewed the new SDK repository assets like the CI configuration and Changelog in any depth. I've taken a cursory look over the rest. Please let me know if you'd like me to give a deeper look at anything specific.

[JoshLove-msft]

Should we delete the snk file if we are not using it?

Leaving for now as we want to use this eventually.

[weshaggard]

Are the "snk" files in this PR needed? Is there a reason they are not using the standard snk files from the eng folder in the repo?

[JoshLove-msft]

Are the "snk" files in this PR needed? Is there a reason they are not using the standard snk files from the eng folder in the repo?

No, they aren't, but we will add new ones once we get them from the service team. The reason for not using the standard ones is that we don't want to change the full assembly name between versions.

[weshaggard]

For the shipping libraries I think it is fine but for the test assemblies there is not reason to have a checked unique key. Also for the test folder I see both a sign.snk and the AzureSdkTestLibKey.snk file. I don't think there should be any reason to have either of those in the test folder.

[ghost]

Hello @JoshLove-msft!

Because this pull request has the auto-merge label, I will be glad to assist with helping to merge this pull request once all check-in policies pass.

p.s. you can customize the way I help with merging this pull request, such as holding this pull request until a specific person approves. Simply @mention me (@msftbot) and give me an instruction to get started! Learn more here.