Add build & release pipeline

[mikoskinen]

Add CI & CD pipelines to Azure DevOps.

TypeGenerator CI and CD -pipelines can be used as examples.

[mikkou-adafy]

Both pipelines have been added. CI pipeline is missing trigger (I did not have right to set it up) and CD is missing release to NuGet.org (should this be already added?).

Tested by running the pipelines and seeing that NugetDownloader can be found in the private feed.