hosts: carve out host out of local profile

To solve #194, we need a way to exclude specifically the host
profiles. By proxy, we might be safe to exclude the host configuration
as a whole.

This change separates the host condfig from other host-local modules
so that we can filter it out in the subsequent commit.

hosts/default.nix

@@ -58,11 +58,12 @@ let
 
   mkHostConfig = hostName:
     let
-      local = {
+      host = {
         require = [
           "${toString ./.}/${hostName}.nix"
         ];
-
+      };
+      local = {
         networking = { inherit hostName; };
 
         _module.args = {
@@ -80,7 +81,7 @@ let
     in
     dev.os.devosSystem {
       inherit system specialArgs;
-      modules = modules // { inherit local lib; };
+      modules = modules // { inherit host local lib; };
     };
 
   hosts = dev.os.recImport