Spike: Provide allowlist/blocklist functionality for ActiveSupport notification event names

[fallwith]

Our current ActiveSupport notifications subscription functionality operates off of fixed lists of event names and/or regex patterns set on a per library basis. All events for a given library are subscribed to by default and they can all be ignored if the instrumentation for the library is itself disabled. For custom notification events which aren't associated with a specific library, we provide an allowlist that defaults to an empty array.

We should explore whether it is useful to offer more fine grained control over ActiveSupport event names that are desired. Perhaps a given Rails library has 5 event names associated with it and you only want to receive information about 2 of them.

Edit: 11/20/25
We've added related support for Active Support Caching and Messaging with #3327

We should create notifications for when new events are added, potentially by looking for changes to the Active Support docs and using our slack notifications for alerts.

[workato-integration]

https://new-relic.atlassian.net/browse/NR-187091