admin: add admin panel for user management

sqlc.yaml

@@ -1,12 +1,12 @@
 version: "2"
 sql:
   - engine: "sqlite"
-    queries: "internal/database/queries.sql"
+    queries: "internal/db/queries.sql"
     schema: "migrations/"
     gen:
       go:
         package: "database"
-        out: "internal/database"
+        out: "internal/db"
         emit_json_tags: true
         emit_prepared_queries: false
         emit_interface: true