Add ptAvatar.findBone method

[dpogue]

This allows getting an avatar's bones using Python, which enables hackery with PtAttachObject to them

[Hoikas]

I think we need to spend some time designing a better system. PtAttachObject has no persistence and doesn't seem like the best method IMO.

[dpogue]

"No persistence" meaning there's no state to be synched to newly joined players? hmm...

A visual issue like that wouldn't be a barrier for my particular use case, but does seem like something worth addressing.

[Hoikas]

Correct. To my mind, I think it would be better to have a more formalized inventory system for attaching objects to the avatar (this system probably involves avatar.sdl) with the ability to anchor objects to the left hip or off-hand built-in, for example. That way, we discourage bespoke solutions in each Age that results in an increased maintenance burden.

[dpogue]

I pulled these comments into a discussion #974 so we can come up with a plan before doing any further implementation.