move plmove, ramp_move, autoattack to namespace

[KorGgenT]

Summary

SUMMARY: Infrastructure "Move game::plmove(), game::ramp_move() and game::autoattack() to avatar_action namespace"

Purpose of change

There's a whoe bunch of functions that don't really live in the right place: these are examples of functions that don't really need to be owned by game.

I chose the name avatar_action because there are a bunch of other functions in game that could also go here, and all of these things have an effect on the player, but may not necessarily want to be owned by avatar either.

Describe alternatives you've considered

putting these functions into the avatar class. i i decided against it because there's a lot of stuff that will go into that class in time anyway, and keeping it to a reasonable size would be a reasonable course of action while it's still in the process of being refactored.

Additional context

I needed to move a couple of things from private to public in game, though some of those will be moved out of game anyway eventually.

[mlangsdorf]

I think I'd rather see these written as avatar_action::move() than defining them inside the namespace's scope, even though they're functionally equivalent. Specifying the namespace inside the definition makes it easier to see when grep'ing.

[KorGgenT]

that's reasonable.