android: Add utility class to determine differences in two lists of objects

This allows determining the difference between two lists in the form of
inserts, updates and deletes (and unchanged elements).

src/frontends/android/app/build.gradle

@@ -49,5 +49,6 @@ dependencies {
     implementation 'androidx.preference:preference:1.2.1'
     implementation 'com.google.android.material:material:1.10.0'
     testImplementation 'junit:junit:4.13.2'
+    testImplementation 'org.assertj:assertj-core:3.24.2'
     testImplementation 'org.mockito:mockito-core:5.8.0'
 }