Consider closing dates in events date filters

[rcantin-w]

#130 (comment)

Mondays and bank holidays would ideally not return any results for "TODAY", unless it's got an exceptional opening (if Monday is on a bank holiday, for example)

We currently handle it on the FE but we could consider it an API rule?

[rcantin-w]

Moving this to Blocked as can't do it until #226 is through and maybe we'll discuss it at planning? Otherwise can be moved back to backlog.

Flagged to Lauren in Slack here.