Support expensive services that don't persist

[sichapman]

• I'm submitting a ...

  • feature request

• What is the current behavior?
  If you have an expensive service that should have staggered startup, but also is a one off job that exits cleanly, there is no healthcheck to exec successfully so the dev env polls forever

• What is the expected/proposed behavior?
  Support some way for the expensive service configuration to allow for exit checks (and exit code?)

• What is the motivation / use case for changing the behavior?
  Support more varied apps