feat(db): add @atomcms/db package skeleton + mysql2/drizzle client

packages/db/tsconfig.json

@@ -0,0 +1,5 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": { "rootDir": "src", "outDir": "dist" },
+  "include": ["src"]
+}