Send `event-reminders-hourly` notification to `#vc-events` and optional second channel

[danieltott]

Related to https://github.com/Virtual-Coffee/cms.virtualcoffee/issues/11 (see comment)

All hourly notifications should be #vc-events. If the event has eventSlackAnnouncementsChannelId set (and that value is not the same as DEFAULT_SLACK_EVENT_CHANNEL, also send it to that channel

[ebanner]

Commenting here to get this issue assigned to me!

https://github.com/Virtual-Coffee/cms.virtualcoffee/issues/11#issuecomment-2181184907