Remote schema permission - allow full access to the remote schema with a wildcard character

Hello all,

We're currently trying to use the remote schema permission feature from the v2 of Hasura and it would be very convenient to be able to specify a full access to the remote schema for a given role by using this syntax :

```yaml

permissions:
- role: user
definition:
schema: "*"

```

The reason is that our remote schema is implementing a large chunk of our business logic (mainly mutations) and it's very painful to synchronize our remote schema types definitions with the remote permissions as we need to dump our entire remote schema into the metadata file each time we evolve our business logic. By accepting a wildcard, we could just refresh the remote schema and that's it. ⚡