Add fingerprint to lock UI

Migrate login UI to conductor
Fix batch add controller not saving EditText content onResume
Prevent double-locking of lock UI
Remove back button from lock UI
Fix login preference not updating

app/src/main/java/exh/util/ViewUtil.kt

@@ -0,0 +1,8 @@
+package exh.util
+
+import android.content.Context
+
+fun dpToPx(context: Context, dp: Int): Int {
+    val scale = context.resources.displayMetrics.density
+    return (dp * scale + 0.5f).toInt()
+}