chore: move config parameter from database to role

The `app.settings.jwt_secret` and `app.settings.jwt_exp` were set at the
database level. Realisticly these only need to be available to the
postgres role.

docker/volumes/db/jwt.sql

@@ -1,5 +1,5 @@
 \set jwt_secret `echo "$JWT_SECRET"`
 \set jwt_exp `echo "$JWT_EXP"`
 
-ALTER DATABASE postgres SET "app.settings.jwt_secret" TO :'jwt_secret';
-ALTER DATABASE postgres SET "app.settings.jwt_exp" TO :'jwt_exp';
+ALTER ROLE postgres IN DATABASE postgres SET "app.settings.jwt_secret" TO :'jwt_secret';
+ALTER ROLE postgres IN DATABASE postgres SET "app.settings.jwt_exp" TO :'jwt_exp';