refactor(keybase): migrate database implementation to keybase package

sqlc.yaml

@@ -1,12 +1,12 @@
 version: "2"
 sql:
   - engine: "sqlite"
-    queries: "db/query.sql"
-    schema: "db/schema.sql"
+    queries: "internal/migrations/query.sql"
+    schema: "internal/migrations/schema.sql"
     gen:
       go:
-        package: "db"
-        out: "db"
+        package: "keybase"
+        out: "internal/keybase"
         emit_json_tags: true
         emit_empty_slices: true
         emit_pointers_for_null_types: true