More fixture applications

[CGA1123]

It would be nice to have at least 1 fixture application to smoke test per available official buildpack.

It might also be good to have a healthcheck as part of that smoke test?

i.e. expect every app to return a 200 OK (with retries?) on the / endpoint at least to verify a clean deploy with a process that can actually start.

This might need to be lenient delayed for slow web servers that take a while to connect to ${PORT}