Add Env and SetEnv methods to command.Meta to retrieve the current
environment name inside any command.
Make sure all calls to Backend.State contain an environment name, and
make the package compile against the update backend package.
Fixes#12154
The "-backup" flag before for "state *" CLI had some REALLY bizarre behavior:
it would change the _destination_ state and actually not create any
additional backup at all (the original state was unchanged and the
normal timestamped backup still are written). Really weird.
This PR makes the -backup flag work as you'd expect with one caveat:
we'll _still_ create the timestamped backup file. The timestamped backup
file helps make sure that you always get a backup history when using
these commands. We don't want to make it easy for you to overwrite a
state with the `-backup` flag.
James Bardin