chore: add manifest fullBackupContent and dataExtractionRules

app/src/main/AndroidManifest.xml

@@ -76,6 +76,8 @@
         tools:replace="android:icon"
         android:name="com.geeksville.mesh.MeshUtilApplication"
         android:allowBackup="false"
+        android:dataExtractionRules="@xml/data_extraction_rules"
+        android:fullBackupContent="false"
         android:icon="@mipmap/ic_launcher2"
         android:label="@string/app_name"
         android:roundIcon="@mipmap/ic_launcher2_round"

app/src/main/res/xml/data_extraction_rules.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<data-extraction-rules>
+    <cloud-backup>
+        <exclude domain="root" />
+        <exclude domain="file" />
+        <exclude domain="database" />
+        <exclude domain="sharedpref" />
+        <exclude domain="external" />
+    </cloud-backup>
+    <device-transfer>
+        <exclude domain="root" />
+        <exclude domain="file" />
+        <exclude domain="database" />
+        <exclude domain="sharedpref" />
+        <exclude domain="external" />
+    </device-transfer>
+</data-extraction-rules>