Output app-profile rather than app-env

[stuartpb]

As per discussion in #5, app-env is changing to refer exclusively to static, non-shell-bound environment variable pairs. The current serialization model used by config writes profile code, not environment values. This will change circa #4, at which point #5 will also be evaluated.

For now, this is the fix that needs to happen, along with tweaks to plushu-addons , plushu services, and plushu-release-env (which will become plushu-release-app-profile).