Add documentation

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

hosts/common/configs/system/documentation/default.nix

@@ -0,0 +1,16 @@
+{ ... }:
+{
+  documentation = {
+    enable = true;
+
+    dev.enable = true;
+    doc.enable = true;
+    info.enable = true;
+    nixos.enable = true;
+
+    man = {
+      enable = true;
+      generateCaches = true;
+    };
+  };
+}