Revert "Use the actual Country type instead of the name."

This reverts commit bd2ec12e0f.

Country is both the data (name, ID, etc) and the container for groups
added to the miz, so it can't be used across multiple mission
generations. See https://github.com/pydcs/dcs/issues/314 for potential
follow up work that would let us do this.

Fixes https://github.com/dcs-liberation/dcs_liberation/issues/2864.

tests/test_factions.py

@@ -41,7 +41,7 @@ class TestFactionLoader(unittest.TestCase):
         with (RESOURCES_DIR / "valid_faction.json").open("r") as data:
             faction = Faction.from_dict(json.load(data))
 
-            self.assertEqual(faction.country.name, "USA")
+            self.assertEqual(faction.country, "USA")
             self.assertEqual(faction.name, "USA 2005")
             self.assertEqual(faction.authors, "Khopa")
             self.assertEqual(faction.description, "This is a test description")