SW Apollyon Rework

[jmcmorris]

I affirm:

• [x] I have paid attention to this example and will edit again if need be to not break the formatting, or I will be ignored
• [x] I have read and understood the Contributing Guide
• [x] I've tested my code and the things my code has changed since the last commit in the PR, and will test after any later commits

What does this pull request do?

Migrate and rework SW Apollyon Limbus area to be in the new battlefield framework. All of this work is heavily based off of the following two captures and other sources: https://www.youtube.com/watch?v=Je5u7C1FCZU https://www.youtube.com/watch?v=LBSlB-CdtMU https://ffxiclopedia.fandom.com/wiki/SW_Apollyon https://www.bg-wiki.com/ffxi/South_West_Apollyon

There are two small related changes in here as well:

• Battlefield groups now support inParty that will put a group into a party
• OnBattlefieldRegister is now actually being called. Eventually I'd like to replace this with just OnBattlefieldInitialise as we really don't need both.

Steps to test these changes

!addkeyitem red_card
!addkeyitem cosmo_cleanse
!pos -600 -0.5 -600 38

https://ffxiclopedia.fandom.com/wiki/SW_Apollyon