This is writing `.DS_Store` files as root in "~/Applications/Home
Manager Apps/<app>", and causing errors during the `rsync` call since it
will try to delete any files that is not present in the app bundle.
Fix#8067.
This is basically a better version of `targets.darwin.linkApps` that
copy apps instead of linking (hence the name). While this is a
convoluted approach, it works with Spotlight, where the previous
approach doesn't. This is also the approach adopted by nix-darwin, see
PR: https://github.com/nix-darwin/nix-darwin/pull/1396.
There are a few particularities about this implementation, for one the
flags we use in rsync are different since we are not using root to copy
the apps to `~/Applications`. This may or may not cause some issues with
specific applications so further testing will be needed. Also the check
for App Management permission needs root (via sudo), so this check is
gated behind a flag that can be disabled if needed.
Fix: #1341.
