Add support for user faction directory.

This allows users to install custom factions to their home directory
rather than the Liberation install directory. Makes it easier to keep
mods across Liberation downloads, and easier for us devs to keep custom
factions without git always wanting us to add them.

game/factions/faction_loader.py

@@ -2,8 +2,9 @@ from __future__ import annotations
 import json
 import logging
 from pathlib import Path
-from typing import Dict, Iterator, Optional, Type
+from typing import Dict, Iterator, List, Optional, Type
 
+from game import persistency
 from game.factions.faction import Faction
 
 FACTION_DIRECTORY = Path("./resources/factions/")
@@ -23,9 +24,16 @@ class FactionLoader:
         if self._factions is None:
             self._factions = self.load_factions()
 
+    @staticmethod
+    def find_faction_files_in(path: Path) -> List[Path]:
+        return [f for f in path.glob("*.json") if f.is_file()]
+
     @classmethod
     def load_factions(cls: Type[FactionLoader]) -> Dict[str, Faction]:
-        files = [f for f in FACTION_DIRECTORY.glob("*.json") if f.is_file()]
+        user_faction_path = Path(persistency.base_path()) / "Liberation/Factions"
+        files = cls.find_faction_files_in(
+            FACTION_DIRECTORY
+        ) + cls.find_faction_files_in(user_faction_path)
         factions = {}
 
         for f in files: