chore: RTP improvements

[Thatsmusic99]

Information

Improves the existing RTP system, with a focus on addressing issues with pre-loaded coordinates that sit outside world borders.

• Renames use-vanilla-border and use-plugin-borders to sync-vanilla-border and sync-plugin-borders respectively.
• The sync options "sync" AT's RTP border limits to their respective borders, i.e. if someone changes the world border radius, then AT will generate coordinates that adhere to the full extent of the border.
• If a border change is noticed (through /at reload or the world border events), then AT will check that each prepared location sits inside the new border. If they don't, new locations are rolled.
• Regardless of whether syncing is enabled, AT will always shrink its coordinate range in response to other borders, i.e. if the Vanilla border is smaller than the configured range set by AT, all the coordinates generated use the Vanilla border as a reference.
• Improved naming conventions across some portions of the code that RTP uses so it is clearer to outside users.

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