[TF] Implement caber kill taunt

[Bitl]

Description

This PR implements a taunt kill onto the Ullapool Caber. Currently, the Caber's taunt consists of the Demoman showing off the Caber, then swinging it. However, it doesn't explode on impact or damage anyone, which I felt was the intended effect.

This taunt works when the Caber is detonated or not, and will do the same damage (500). If the Caber hasn't been detonated, the player will also be damaged as well, similar to the Equalizer taunt.

This PR is meant to be used in conjunction with #1456, as the "detonated" version of the kill taunt registers as a melee kill.

Videos:

Un-detonated:

https://github.com/user-attachments/assets/4e6965d6-a0d1-4cc0-a53e-db7ea8830625

Detonated:

https://github.com/user-attachments/assets/4b6ab298-4ca5-4b8c-a5cd-e4b76bfc4fda

[Bitl]

Updated PR to work with latest SDK code

[Bitl]

Converted to draft to sync it with the repo.

[Bitl]

This PR will be further updated when and if #1702 gets implemented, as it includes further alterations to the Caber that cannot be merged here without it getting added.