mechanic: move word lists to data files

The word lists (monsters, spells, equipment, races, classes, titles and
so on) now live in pqcli/data/*.json instead of pqcli/config.py. A
GameData object loaded at startup is passed to the simulation and UIs.

Users can replace any list by putting NAME.json in
$XDG_CONFIG_HOME/pqcli/data/ or a directory given with --data-dir.
--dump-data DIR copies the built-in files out for editing. Malformed
files are reported and pqcli exits before starting the UI.

Combat task descriptions come from the new combat_verbs list, with
{target} standing for the enemy. The built-in list holds only "Executing
{target}", and a single verb consumes no random roll, so stock gameplay
is unchanged. Recorded traces in tests/fixtures pin this down.

Monster, Race and Class stay in pqcli.config so existing saves still
load.

Resolves #3

pqcli/ui/base.py

@@ -2,6 +2,7 @@ import abc
 import argparse
 import typing as T
 
+from pqcli.game_data import GameData
 from pqcli.mechanic import Player
 from pqcli.roster import Roster
 
@@ -12,8 +13,10 @@ class BaseUserInterface(abc.ABC):
         roster: Roster,
         player: T.Optional[Player],
         args: argparse.Namespace,
+        data: GameData,
     ) -> None:
         self.roster = roster
+        self.data = data
         self.args = args
         self.player = player