adds log update function and log list

- log updates in background automatically
  from server data
- log list in main screen of app is updated
  showing the title of each notification

app/src/main/res/layout/fragment_first.xml

@@ -45,6 +45,7 @@
         app:layout_constraintStart_toStartOf="parent"/>
 
     <LinearLayout
+        android:id="@+id/buttons"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:orientation="horizontal"
@@ -68,4 +69,35 @@
             android:textColor="@color/white"
             android:text="@string/view_sender" />
     </LinearLayout>
+
+    <LinearLayout
+        android:id="@+id/header"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal"
+        android:layout_marginTop="20dp"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintTop_toBottomOf="@id/buttons"
+        app:layout_constraintStart_toStartOf="parent">
+    <TextView
+        android:id="@+id/nr_messages"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="@string/default_nr_messages"
+        android:layout_marginEnd="10dp"
+        android:textSize="20sp"/>
+    <TextView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="@string/message_header"
+        android:textSize="20sp"/>
+    </LinearLayout>
+
+    <ListView
+        android:id="@+id/notification_list"
+        android:layout_width="match_parent"
+        android:layout_margin="20sp"
+        android:layout_height="wrap_content"
+        app:layout_constraintTop_toBottomOf="@id/header">
+    </ListView>
 </androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/notification_item.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content">
+
+    <TextView
+        android:layout_width="match_parent"
+        android:layout_height="10dp" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>

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

@@ -13,6 +13,8 @@
     <string name="scan_sender">Scan</string>
     <string name="camera_fragment_label">Scan Sender QR</string>
     <string name="preference_file_key">code_file_key</string>
+    <string name="message_header">messages received:</string>
+    <string name="default_nr_messages">0</string>
     <string name="code_key">code_key</string>
     <string name="notification_title">Bump</string>
     <string name="bump_notification_channel_id">bump_id</string>