Don't enforce web as procfile entry

[david-caro]

This allows using any other name, and will use the first one it find as the default command.

We might want to change the way we start bulidservice images too to pick the web procfile entry, or not :)

Bug: T336050

[supertassu]

We might want to change the way we start bulidservice images too to pick the web procfile entry, or not :)

I think we should do that, yes.

[david-caro]

We might want to change the way we start bulidservice images too to pick the web procfile entry, or not :)

I think we should do that, yes.

I think that it would be a good idea to allow the user to start different applications (be that webservices or not), and for that, they could use the same image, just changing the entrypoint (see https://phabricator.wikimedia.org/T337191#8870190).

This would mean in the future having something like 'toolforge app start --command frontend' and something like 'toolforge app start --command backend' using the same buildservice image, but just different entrypoints in the procfile.

Though as we currently only have webservice, it might make sense to use web for it, but once we have more than one, we should allow the user to specify whichever they want 👍

[NdibeRaymond]

+1. building was successful