More complex announcement settings

[NovaFox161]

Is your improvement request related to a problem? Please describe.
Add the ability to have more complex settings for announcements, so that one can set the announcement to announce during, or even after an event has occurred.

Describe the solution you'd like
Add a flag that allows setting an announcement to be posted before, during, or after an event.

Describe alternatives you've considered
N/a

Additional context
This is already roughly implemented in the backend, but beyond the database and object properties, is not really handled, effectively a hidden setting. I have yet to fully flesh out the code for actually handling how those announcements will be calculated, but implementing it in the front end should essentially be plug and play.