Azure CI - Make built Example executable available as a build output

[bryphe]

Per @manuhornung suggestion on Discord - as part of our website - it'd be great to have the sample 'Example.exe' demo application available for download, so that users can test out the components and see what is currently available.

This will also help us get a little wider testing in terms of the compatibility of the compiled binary with a variety of systems, and give us a heads up if there are any additional blockers to getting release out the door.

Work needed to enable this:

• Add an esy release step for each platform has part of our CI build
• Add the released binary as a 'publish artifact' in Azure CI
• Validate the built binaries for each platform

[bryphe]

If anyone is interested in learning more about Azure CI, or cross-platform builds with esy - this could be an interesting issue. A good example to look at is the work @ulrikstrid to make esy release work with the hello-reason app here: https://github.com/esy-ocaml/hello-reason/pull/15

[ulrikstrid]

Feel free to ping me on Discord if you want any input. Might also be interesting to follow this PR https://github.com/esy/esy/pull/842 as it will allow esy release for Windows

[Et7f3]

Some useful link https://devblogs.microsoft.com/devops/automating-releases-in-github-through-azure-pipelines/