Exclude break and filler events like sleep and intermissions

[Aldaviva]

The schedule unfortunately insists on putting fake runs in empty times when nothing is happening, like intermissions between days in schedules that aren't 24 hours per day, for example the "Sleep" events in GDQ Express 2023. These result in unnecessary clutter in the calendar, and unhelpful alerts that no one cares about.

These are hard to identify because there is no consistent naming or tagging for these filler events, so it might just be subject name whack-a-mole each time they dream up a new one.

Identifying filler events

• Subject: Intermission$, duration > 14h (GDQ Express 2023)
• Subject: ^Sleep$, duration > 11h (Flame Fatales 2023)
• Subject: ^Sleep$, duration > 11h (Frost Fatales 2023)
• Subject: ^Sleep$, duration > 0 (Flame Fatales 2022)

The duration, host, runners, and subject are all unreliable, but subject seems the most consistent.

Maybe a heuristic like this would work:

subject == "Sleep" || duration > TimeSpan.FromHours(11)

[Aldaviva]

Released as 2.2.0.