Saving of allowed keys

OpenKeychain/src/main/res/layout/api_app_settings_activity.xml

@@ -33,6 +33,18 @@
                     android:layout_height="wrap_content"
                     tools:layout="@layout/api_app_settings_fragment" />
 
+                <TextView
+                    style="@style/SectionHeader"
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:text="@string/api_settings_allowed_keys" />
+
+                <FrameLayout
+                    android:id="@+id/api_allowed_keys_list_fragment"
+                    android:layout_width="match_parent"
+                    android:layout_height="match_parent"
+                    android:orientation="vertical" />
+
                 <TextView
                     style="@style/SectionHeader"
                     android:layout_width="match_parent"