Add --push-secrets option to exec for pushing .env files

[anatoly-pashin-axon21]

This is meant to replace #1223: as it was mentioned in the discussion, a flag might be a better option.

[djmb]

Thanks for the PR @anatoly-pashin-axon21.

I think we need a couple of changes here:

1. We should also allow --push_secrets for the interactive app exec.
2. We should raise an exception if --push_secrets is combined with --reuse

[anatoly-pashin-axon21]

@djmb the comments are addressed, please review again