RIP: MultiMystery and Mystery, now there's just Generate

Other changes:
host.yaml Multi Mystery options were moved and changed
generate_output now has an output_directory argument
MultiWorld.get_game_players(<game>) now replaces <game>_player_ids
Python venv should now work properly

WebHostLib/static/assets/zelda3/player-settings.js

@@ -173,6 +173,9 @@ const generateGame = (raceMode = false) => {
   }).catch((error) => {
     const userMessage = document.getElementById('user-message');
     userMessage.innerText = 'Something went wrong and your game could not be generated.';
+    if (error.response.data.text) {
+      userMessage.innerText += ' ' + error.response.data.text;
+    }
     userMessage.classList.add('visible');
     window.scrollTo(0, 0);
     console.error(error);