chore: move next admin packages to core repo (#5983)

**What**
- Move packages for `next` version of admin to core repo

**Other**
- Since this PR introduces packages that depend on Vite 5, it also introduces @types/node@^20. We have never had a direct dependency on the types package for Node, and as far as I can see that has resulted in us using the types from Node.js@8, as those are a dependency of one of our dependencies. With the introduction of @types/node@^20, two of our packages had TS errors because they were using the NodeJS.Timer type, which was deprecated in Node.js@14. We should add specific @types/node packages to all our packages, but I haven't done so in this PR to keep it as clean as possible.
- Q: @olivermrbl I've added the new packages to the ignore list for changeset, is this enough to prevent them from being published?

.eslintrc.js

@@ -224,6 +224,27 @@ module.exports = {
         ],
       },
     },
+    {
+      files: ["packages/admin-next/dashboard/**/*"],
+      env: { browser: true, es2020: true, node: true },
+      extends: [
+        "eslint:recommended",
+        "plugin:@typescript-eslint/recommended",
+        "plugin:react-hooks/recommended",
+      ],
+      ignorePatterns: ["dist"],
+      parser: "@typescript-eslint/parser",
+      parserOptions: {
+        project: "./packages/admin-next/dashboard/tsconfig.json",
+      },
+      plugins: ["react-refresh"],
+      rules: {
+        "react-refresh/only-export-components": [
+          "warn",
+          { allowConstantExport: true },
+        ],
+      },
+    },
     {
       files: ["packages/admin-ui/lib/**/*.ts"],
       parser: "@typescript-eslint/parser",