Our use case involves a custom provider, and we'd like to lock down the TUI to just this provider.

Currently, since the provider config is a blocklist, we need to update the config every time the provider list changes. Instead, it would be nice to have an enabled_providers config array, which only enables the providers that are supplied.

In the case of a conflict between enabled and disabled, the disabled option would take priority, to support backwards compatibility.

If this is a desired feature, and not already on the backlog, I'd be happy to have a stab at contributing this.