Clean up shared code between `batch apply` and `preview`
Created by: mrnugget
This is a follow-up to #511 and #512.
It cleans up the code that's shared between batch apply
and previe
by trying to make the boundaries between the "TUI +
execution"-glue-code, the service
pkg, the executor
pkg and the
helpers clearer.
A lot of this is subjective, of course (what does "clearer" even mean, man), but I think less duplication is Good and less cross-talk between a trio of components too.