Return error details when `pipelines:setup` fails

[wadewegner]

(I believe this is related to #83 but manifests and error that is a blocker for pipelines:setup.

When running the pipelines:setup command I got the error:

 ▸    Couldn't create application ⬢ pipelinedeleme-staging: invalid app.json

Digging in, it seems it's because my app.json requires vars that aren't set on the pipeline. Something like:

 "manifest_errors": [
    "config var \"DEV_HUB_SFDX_AUTH_URL\" is required",
    "config var \"SFDX_BUILDPACK_DEBUG\" is required"
  ],

However, that error wasn't exposed to me. I had to get support.

It would be good return the error so the developer knows what needs to be fixed.

As an aside, it appears that there's no way to resolve this with pipelines:setup because I don't have a way to run setup on a pipeline and set of apps that are already configured, and the command itself doesn't expose a way to set these vars.

[raulb]

@wadewegner thanks for bring this up to our attention. We'll look into ways to expose those errors back to the users. Agreed the current UX is not great.