refactor(db): move to core package (#4589)

apps/nextjs/next.config.ts

@@ -1,6 +1,6 @@
 // Importing env files here to validate on build
 import "@homarr/auth/env";
-import "@homarr/db/env";
+import "@homarr/core/infrastructure/db/env";
 import "@homarr/common/env";
 import "@homarr/core/infrastructure/logs/env";
 import "@homarr/docker/env";