Refactor NixOS and Home Manager modules

This makes them more modular and configurable by allowing features to be
enabled per-host.

Squashed commit of the following:

commit e9896d6166125de7aa26ddc63dac3adb196e8c23
Author: Oliver Davies <oliver@oliverdavies.dev>
Date:   Mon Nov 25 23:06:23 2024 +0000

    Use mkMerge

    To ensure features isn't overridden and values aren't lost accidentally

commit c9c8ff5d059f08ade3aee9bb4e25bd51d4817a6d
Author: Oliver Davies <oliver@oliverdavies.dev>
Date:   Mon Nov 25 22:56:38 2024 +0000

    Move NixOS module imports

commit 4a85bbac9dfa8f06825f6b1fee45ef27befa16d3
Author: Oliver Davies <oliver@oliverdavies.dev>
Date:   Mon Nov 25 22:39:54 2024 +0000

    Move Home Manager module imports

commit 6d7a1b0aac68ccc8649fa2d8cd6e8b17ecebb4f0
Author: Oliver Davies <oliver@oliverdavies.dev>
Date:   Mon Nov 25 21:15:54 2024 +0000

    Add host-specific Home Manager configurations

commit b32da2fbf7498c9684d8289be0f02800994e9110
Author: Oliver Davies <oliver@oliverdavies.dev>
Date:   Mon Nov 25 18:00:00 2024 +0000

    Start to parameterise Home Manager modules

commit e80e89b415849cc4c6051a07b70587ac98724e2c
Author: Oliver Davies <oliver@oliverdavies.dev>
Date:   Mon Nov 25 18:00:00 2024 +0000

    Rename wsl commands to home-manager

commit 6d82ed73da3c104fb25117fb843c3f3b5d833180
Author: Oliver Davies <oliver@oliverdavies.dev>
Date:   Mon Nov 25 18:00:00 2024 +0000

    Refactor NixOS Home Manager configuration

commit cc5cbf5ac1a407a456d7258dd65a78ba3128a88f
Author: Oliver Davies <oliver@oliverdavies.dev>
Date:   Mon Nov 25 08:05:00 2024 +0000

    Refactor WSL Home Manager configuration

commit deaf664a0997871b6f2bb0a8f97d638a91cb10bc
Author: Oliver Davies <oliver@oliverdavies.dev>
Date:   Mon Nov 25 08:04:00 2024 +0000

    Refactor lemp11 configuration

run

@@ -25,6 +25,14 @@ function help {
   printf "\nExtended help:\n  Each task has comments for general usage\n"
 }
 
+function home-manager:build {
+  _home build "$@"
+}
+
+function home-manager:switch {
+  _home switch "$@"
+}
+
 function nixos:build {
   _nixos build "$@"
 }
@@ -41,23 +49,14 @@ function update {
   nix flake update
 }
 
-function wsl:build {
-  _home build wsl2 "$@"
-}
-
-function wsl:switch {
-  _home switch wsl2 "$@"
-}
-
 function _home {
   local command="$1"
-  local flake="$2"
-  shift 2
+  shift 1
 
   NIXPKGS_ALLOW_UNFREE=1 home-manager "$command" \
     --extra-experimental-features flakes \
     --extra-experimental-features nix-command \
-    --flake ".#$flake" \
+    --flake ".#$(whoami)@$(hostname)" \
     --impure "$@"
 }