chore: use viewport rendering mode, increase default gravity setting

Author: NathanLovato

Diff for: project.godot

@@ -59,6 +59,7 @@ CameraMode="*res://CameraMode/CameraMode.tscn"
 window/size/viewport_width=1920
 window/size/viewport_height=1080
 window/size/mode=3
+window/stretch/mode="viewport"
 
 [input]
 
@@ -141,3 +142,7 @@ pause={
 3d_physics/layer_1="Entities"
 3d_physics/layer_2="Level"
 3d_physics/layer_3="Coins"
+
+[physics]
+
+3d/default_gravity=16.0