global/persist: generalize persist locations

modules/global/persist.nix

@@ -0,0 +1,20 @@
+{ config, lib, ... }:
+with lib;
+{
+  persist = {
+    directories = [
+      "/home"
+      "/etc/nixos"
+      "/etc/nixos-private"
+
+      "/var/log"
+      "/var/lib/systemd/coredump"
+      "/var/lib/tailscale"
+
+      "/root/.ssh"
+    ];
+    files = [
+      "/etc/machine-id"
+    ];
+  };
+}

modules/modules/hardware/audio.nix

@@ -20,5 +20,9 @@ in
       pulse.enable = true;
       alsa.enable = true;
     };
+
+    persist.directories = [
+      "/var/lib/alsa"
+    ];
   };
 }

modules/modules/hardware/form.nix

@@ -57,6 +57,10 @@ in
         variables.LAPTOP = "True";
         systemPackages = with pkgs; [ acpi brightnessctl ] ++ optional config.powerManagement.powertop.enable pkgs.powertop;
       };
+
+      persist.directories = [
+        "/var/lib/systemd/backlight"
+      ];
     })
 
     (mkIf cfg.portable {

modules/modules/hardware/peripherals/fprint-sensor.nix

@@ -8,4 +8,8 @@ in
   options.modules.hardware.peripherals.fprint-sensor = mkOpt types.attrs { };
 
   config.services.fprintd = mkAliasDefinitions options.modules.hardware.peripherals.fprint-sensor;
+
+  config.persist.directories = mkIf cfg.enable [
+    "/var/lib/fprint"
+  ];
 }

modules/modules/hardware/wireless.nix

@@ -26,6 +26,10 @@ in
     (mkIf cfg.bluetooth.enable {
       hardware.bluetooth.enable = true;
       services.blueman.enable = cfg.bluetooth.blueman.enable;
+
+      persist.directories = [
+        "/var/lib/bluetooth"
+      ];
     })
     (mkIf cfg.wifi.enable {
       networking.wireless = {

modules/modules/virtualization.nix

@@ -16,5 +16,8 @@ in
     };
     programs.dconf.enable = true;
     environment.systemPackages = with pkgs; [ virt-manager docker-compose ];
+    persist.directories = [
+      "/var/lib/libvirt"
+    ];
   };
 }