Implement Charge Stance properly

[fatcerberus]

Charge Stance was implemented very lazily; it just takes the first action of Charge Slash and prepends that to the selected move's actions. This causes the turn preview to be incorrect and requires the engine to modify the skill data prior to queuing actions, which may have other unforeseen issues.

Ideally, the Charge turn should be implemented as a basic action in the battle engine, tied to the Stance. Modifying skill data on-the-fly outside of a status or field condition is tacky so it would be best to avoid any solution involving such manipulation.

[fatcerberus]

I'm actually not sure how the move data manipulation interacts with statuses. I'll need to check that.