Deprecate "Live Twin" tag

BUR #12058 has been rejected.

deprecate live_twin

There's a tag called Live Twin which currently serve no purposes. I guess someone who tag this wanted to use this tag for depiction of Live Twin Lil-la and Live Twin Ki-sikil together, but their respective character tag is suffice to clarify this.

Makes sense. live twin predates the character tags. Now the character tags exist it serves little point.

It seems that it was supposed to be an yugioh archetype tag for "Live Twin", but yeah, the current character tags are already more than enough. I would suggest to nuke it as well.

I just nuked it.

The bulk update request #12058 (forum #220394) has been rejected by @nonamethanks.