Clarify usage of hab config apply

[christophermaier]

The documentation example for hab config apply at https://www.habitat.sh/docs/using-habitat/#config-updates can be misleading. By using a single key-value pair (and by the fact that the command is called apply), it can lead users to think that the Supervisor will "remember" the current configuration and just add the new value on top of it, which is distinctly not the case.

Having a more complete example, along with a more detailed explanation of the layering of configuration that happens (e.g., default.toml as base, with environment, user.toml, and hab config applyd config layered on top of that) would help clarify how things are actually behaving.

[rsertelon]

This is linked to #1059 I think

[tduffield]

Just to add onto this, documenting the /hab/user directory to some degree would be nice as well. I noticed a deprecation message saying I needed to move my user.toml to /hab/user/<svc>/config and didn't really have any guidance as to what /hab/user even was.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. We value your input and contribution. Please leave a comment if this issue still affects you.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. We value your input and contribution. Please leave a comment if this issue still affects you.