WebHost: add a tracker api endpoint (#1052)

An endpoint from the tracker page.

WebHostLib/api/__init__.py

@@ -11,5 +11,5 @@ api_endpoints = Blueprint('api', __name__, url_prefix="/api")
 def get_players(seed: Seed) -> List[Tuple[str, str]]:
     return [(slot.player_name, slot.game) for slot in seed.slots.order_by(Slot.player_id)]
 
-
-from . import datapackage, generate, room, user  # trigger registration
+# trigger endpoint registration
+from . import datapackage, generate, room, tracker, user