Reformat repository using new nixfmt-rfc-style.
Instead of having to manually stub packages that should not be downloaded we instead automatically stub all packages (except a small list of whitelisted ones). Tests can re-introduce the real package by using the `realPkgs` module argument.
background
This leads to a considerably slower expansion time for snippets, which severely degrades the user experience. Also, the launchd plist from the source omits this key: 8daadcc949/espanso/src/res/macos/com.federicoterzi.espanso.plist PR #5411
8daadcc949/espanso/src/res/macos/com.federicoterzi.espanso.plist
