Fix bodyswap to work on the latest adv-beta

[Crystalwarrior]

Also adds automatic re-centering on the unit you bodyswapped to!

[myk002]

also needs a line in the changelog. New Tools, "reinstated" format.

[myk002]

needs "reinstated" changelog entry

[myk002]

As rome of oxtrot mentioned on Discord, please also add your name to Authors.rst

[myk002]

code looks reasonable, but from Discord I'm gathering there are still open questions about the behavior of this script, is that right?

btw still needs changelog.txt entry

[myk002]

needs changelog entry

[Crystalwarrior]

Since this fixes the functionality the script came with originally, step 2 is making the script not auto add to core party and resolve any retire issues on adventurers that become wanderers post body swap and look into how the game handles those units

[myk002]

Could you create an issue on GitHub detailing the surrounding issues you've found with the script's behavior? I want to make sure they're recorded so we don't forget about them.