extend configurables, optimize image stretching

app/src/main/res/drawable/splash_style.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item>
+        <shape android:shape="rectangle">
+            <solid android:color="@color/white" />
+        </shape>
+    </item>
+    <item>
+        <bitmap android:src="@drawable/splash"
+                android:gravity="center"
+                android:tileMode="disabled"/>
+    </item>
+</layer-list>

app/src/main/res/values/themes.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <style name="Theme.GakumasLocalify" parent="@style/Theme.MaterialComponents.Light.NoActionBar" >
-        <item name="android:windowBackground">@drawable/splash</item>
+        <item name="android:windowBackground">@drawable/splash_style</item>
     </style>
 
     <style name="Theme.GakumasLocalify.NoDisplay" parent="@style/Theme.MaterialComponents.Light.NoActionBar" >