Add Yahtzee image and update .gitignore

Introduce `Yahtzee.png` with corresponding import settings in the project. Update `.gitignore` to include new export files for the Yahtzee APK.

.gitignore

@@ -6,3 +6,7 @@
 Kniffel.apk
 
 Kniffel.apk.idsig
+
+android export/Yahtzee.apk
+
+android export/Yahtzee.apk.idsig

android export/Yahtzee.png.import

@@ -0,0 +1,34 @@
+[remap]
+
+importer="texture"
+type="CompressedTexture2D"
+uid="uid://1clq1yvfylal"
+path="res://.godot/imported/Yahtzee.png-f5719d210616c44aa8db0a036c144597.ctex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://android export/Yahtzee.png"
+dest_files=["res://.godot/imported/Yahtzee.png-f5719d210616c44aa8db0a036c144597.ctex"]
+
+[params]
+
+compress/mode=0
+compress/high_quality=false
+compress/lossy_quality=0.7
+compress/hdr_compression=1
+compress/normal_map=0
+compress/channel_pack=0
+mipmaps/generate=false
+mipmaps/limit=-1
+roughness/mode=0
+roughness/src_normal=""
+process/fix_alpha_border=true
+process/premult_alpha=false
+process/normal_map_invert_y=false
+process/hdr_as_srgb=false
+process/hdr_clamp_exposure=false
+process/size_limit=0
+detect_3d/compress_to=1