This adds some new `data/text/` files, which are the new home for
item/move/ability descriptions, as well as in-game messages, in one
place for ease of translation.
`BattlePokedex` is now `Pokedex`, `BattleItems` is now `Items`, etc.
I also renamed `Movedex` to `Moves` and `Statuses` to `Conditions`.
`TypeChart` isn't `Types` yet, because unlike the others, it's not
indexed by ID. That should probably be fixed one day.
It's a judgment call that doesn't belong among the other factual
information in `moves.ts`.
The information is still around; in the client's `battle-dex-search.ts`
in `BattleMoveSearch#moveIsNotUseless`. But now it's all in one place.
fb18721e82
BasicEffect always had a `status` property to support the pattern of
testing it to see if it's a move that sets status directly.
This is just a situation that TypeScript is bad at.
Another possibility would be to set `status: undefined` on PureEffect,
Ability, Item, and Species, but I think that's also ugly. Casting to
Move is probably the best approach, so that's what we do now.
