nixos/public-inbox: bind key and cert paths

Otherwise, these can't be accessed by the service.

Alyssa Ross e1996d7b eb00bbcd

Changed files
+4
nixos
modules
services
+4
nixos/modules/services/mail/public-inbox.nix
···
"${config.i18n.glibcLocales}"
]
++ mapAttrsToList (name: inbox: inbox.description) cfg.inboxes
+
++ filter (x: x != null) [
+
cfg.${proto}.cert or null
+
cfg.${proto}.key or null
+
]
++
# Without confinement the whole Nix store
# is made available to the service