Add an event listing to Umami (to show off core's datetime handling)

I'm notoriously opinionated about datetime and some other admin UI issues, so I'll chime in a few thoughts, based on what I would consider best practices:

• I agree with having a view specifically for managing events, but I also think that whenever possible we should give admins and editors the opportunity to manage or add least add to content in the public view. So long as permission are followed, there's no reason they should have to go to a completely separate interface. For example, including something like #3133235: Make views "add content" link for specific bundle, option for custom text
• I strongly dislike the way core's datetime range forces a user to manually enter a value for every field, unless using a default that often isn't useful (e.g. now or now + offset). With no default on a standard datetime range field, you would need to manually populate 14 fields for a single range (if using am/pm). The calendar software most people are used to have a concept of duration (@dww I know you and I have discussed this previously) with a default (e.g. one hour), so that having entered the starting set of values, the end set can be populated automatically, and tweaked if necessary
• For typical applications (e.g. meetings) the inclusion of the seconds value isn't helpful
• As a default, now or "now + offset" aren't what people encounter in common calendar applications. Usually it's more like "next hour"

I will also add that I created the Smart Date Starter Kit as a way to package together what I consider best practices as an easy-to-manage configuration for events. If we want a contrib space to hammer out some ideas on what we think a "best of breed" solution could look like, that (or something similar) could work as a place collaborate on ideas and make them tangible before getting into the work of moving the final changes into core.

I like this idea (speaking as a maintainer of Umami).

I don't know enough about dates/date fields/date range/etc to be a great help (except I know how frustrating it is to try set up event content types as a site builder.

The only item of issue I have here is that after a while all the events will be out of date as time passes, so we need to figure out some way to put (at least some of the events in the future). Maybe part of the migration script for installing Umami can set the dates for specific events as one one, one week, one month, two months, etc from "now".

Great point about being able to create event with an offset from the time of installation. Maybe this script could also be used to manually "refresh" event date so they're recent or upcoming rather than in the distant past.

I wonder should we mark this issue as 'Postponed' for two reasons:

1. It doesn't look like any one has worked on it since it was created 2 years ago, and
2. We don't have an events content type in Umami so it would be impossible to create an events listing.

That sounds fair @dww.

I'll leave it as is for now so and if someone feels like firing up the blender later, we'll be waiting with open arms (and bandages).