Continious integration using Azure Pipe Lines

[michaelp]

• This PR is part of the work on the issue Performance degradation in recent commits #44. The goal is to have continuous integration and to run the build and tests on every commit.
• I choose Azure pipelines since they are free and I find their integration with Github superior to other alternatives
• This web page demonstrates the integration enabled and running on my fork of this repository
• Please notice that I deliberately run the tests only using dotnet core and inside Linux
• My intention is to have Continuous integration available prior to my next pull request
• @ironfede please turn on the integration with azure pipelines on this repository. This PR has the necessary configuration files and if you have any questions please send me an email directly

[Numpsy]

I choose Azure pipelines since they are free and I find their integration with Github superior to other alternatives

Would there be any thoughts or objections to the idea of changing it to use GitHub actions?

Reasoning: The current CI setup doesn't seem to integrate status reporting into pull requests (even though the builds are actually being done over in Azure), and I think GitHub actions is up to doing everything needed now (running the CI builds on both Windows and Linux for example)

[Numpsy]

Ok, looking again I see that there are results visible here for merges to the main branch, but not for pull requests, so maybe it's just that the config needs tweaking to get PR results.