Allow CMD other than curl and wget

[lionello]

Fixes flask sample which uses python for healthcheck.

We now allow any healthcheck, as long as we can find an "localhost" host URL somewhere in the cmd. Also relaxing the NONE healthcheck to allow for args, since we'd ignore them anyway.

• post-merge: uptake latest defang mod in backend
• update healthcheck parsing in defang_service

[jordanstephens]

Do we have a place in the docs to capture things like this where defang requires something more narrow than docker requires in the compose file?

[lionello]

Do we have a place in the docs to capture things like this where defang requires something more narrow than docker requires in the compose file?

No. Just in our tests. See tests folder. Would be great to document, but that's going to be out of date real fast. Generate docs from tests? 🤔