add module for device-specific config

in principle this module declares the config that's defined in
devices/foo/default.nix

modules/base.nix

@@ -52,38 +52,11 @@ in {
       type = types.attrsOf types.anything;
     };
     boot = {
-      dts = {
-        src = mkOption { type = types.path; };
-        includes = mkOption {
-          default = [];
-          type = types.listOf types.path;
-        };
-      };
       commandLine = mkOption {
         type = types.listOf types.nonEmptyStr;
         default = [];
       };
     };
-    device = {
-      defaultOutput = mkOption {
-        type = types.nonEmptyStr;
-      };
-      flash = {
-        address = mkOption { type = types.str; };
-        size = mkOption { type = types.str; };
-      };
-      loadAddress = mkOption { default = null; };
-      entryPoint = mkOption { };
-      radios = mkOption {
-        type = types.listOf types.str;
-        default = [];
-        example = ["ath9k" "ath10k"];
-      };
-      rootDevice = mkOption { };
-      networkInterfaces = mkOption {
-        type = types.attrsOf types.anything;
-      };
-    };
   };
   config = {
     defaultProfile.packages = with pkgs;