Feature request: Add festival detection.

[brybrant]

Detecting whether a festival is active or not would be great for /daily, /notifier daily, and /reminder event for subscribing to festival events that run on a fixed schedule:

Halloween Your Mad King Says...

Festival of the Four Winds Skimmer Race Fishing Tournament Dolyak Race Skiff Race Treasure Hunt

Dragon Bash Hologram Stampede

...

Apparently the official method for getting the current active festival has been broken since 2017 😕

Pending https://github.com/arenanet/api-cdi/issues/489