[lua] Implement BST Ability "Killer Instinct"

[UmeboshiXI]

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• I have read and understood the Contributing Guide and the Code of Conduct.
• I have 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?

Implements missing BST Merit ability "Killer Instinct"
https://www.bg-wiki.com/ffxi/Killer_Instinct
https://ffxiclopedia.fandom.com/wiki/Killer_Instinct

Killer Instinct is similar to other job circle abilities. It applies to nearby party members and grants killer effects to them.

For this ability, the killer effect granted depends on the ability caster's current pet(See monster correlation)
https://ffxiclopedia.fandom.com/wiki/Beast_Strength_Chart

If the player has no pet out, the ability can not be used.

If a pet is despawned or killed, the effect does not wear off.

Steps to test these changes

1. !additem fish_broth
2. !getmod amorph_killer on self.
3. Use Killer Instinct
4. !getmod amorph_killer on self. See increase of mod.
5. Test other pets for other mods and see they grant the corresponding killer mods.
   5a. Test on a party member, see party member also gain mods.

[wccbuck]

Cool, this can also be expanded upon eventually in conjunction with this PR #7477

[Xaver-DaRed]

Overall good. Do make the changes Sruon proposed, please.