Warn users to apply licenses to self-hosted instances

Logical changes:

1. When creating or editing a self-managed cluster, the API will track if we haven’t applied a license yet (on a per-instance basis).
2. Let’s nag them:

1. When a cluster has an instance in this “nag list”, we’ll show a tooltip on the card, “Please sign in and apply your new licenses!” and guide them to the instances list.

1. Unless it has a self managed FQDN too, then we can guide them to sign in to the cluster.

2. When an instance is in this “nag list”, we’ll show a tooltip on each of the instances, “Please sign in and apply your new license!” or something like that. Show the user a sign-in button for the instances.
3. Once signed in to the cluster FQDN or instance, we’ll:

1. Check if they’ve applied their license. If they have, we’ll clear the nag. (`get_usage_licenses` can answer that, I think)
2. If they haven’t, we’ll show a warning banner or something guiding them to the config page to apply their new license.

3. On the config page:

1. After we `install_usage_license` :

1. Clear the nags once the instance(s) are updated by calling a new API in CM

4. When logging in to a cluster or instance, check `get_usage_licenses` to handle license states:

1. If we find valid license(s), clear the nagging by calling a new API in CM