Update packwiz repo format

instance/.minecraft/options.txt

@@ -0,0 +1,2 @@
+darkMojangStudiosBackground:true
+skipMultiplayerWarning:true

instance/instance.cfg

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+InstanceType=OneSix
+iconKey=mtr
+name=MTR-LetsPlay
+OverrideCommands=true
+PreLaunchCommand=\"$INST_JAVA\" -jar packwiz-installer-bootstrap.jar https://raw.githubusercontent.com/Minecraft-Transit-Railway/LetsPlay-Packwiz/master/pack.toml

instance/mmc-pack.json

@@ -0,0 +1,14 @@
+{
+    "components": [
+        {
+            "important": true,
+            "uid": "net.minecraft",
+            "version": "1.20.4"
+        },
+        {
+            "uid": "net.fabricmc.fabric-loader",
+            "version": "0.16.14"
+        }
+    ],
+    "formatVersion": 1
+}