[core, sql] Allow customized spawn times for TOTD mobs

[sruon]

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What does this pull request do?

• Adds 2 columns to mob_spawn_points: spawnTime, despawnTime. NULL-able
• Sets it on CMobEntity when set in SQL
• Spawn handler accounts for it (higher priority than existing SPAWNTYPE_)
• Sets the proper values according to 🔨 Implement Nighttime Bat timeslots by ID #10408 (the bats + all undeads in Zitah)
• Drop the TOTD routing (time server -> spawn handler) in favor of Vanadiel game hours
  • Aware it removes some code from CInstance but I believe it was bugged to begin with and it should now correctly forward TOTD events to instances. Not that any instance makes use of it at the moment.
• Bunch of tests including spawn slots

Closes #10408

Steps to test these changes

Draft for a few days while I'm out

[github-actions]

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[zach2good]

An alias for using SpawnWindow = std::pair<uint8, uint8>; would help this code a lot, or a struct to a similar effect