Allow selection of a CA certificate for a VPN profile

This solution is just temporary as it really is not that user-friendly
to select CA certificates with a Spinner widget.

src/frontends/android/res/layout/profile_detail_view.xml

@@ -79,6 +79,31 @@
             android:inputType="textPassword|textNoSuggestions"
             android:hint="@string/profile_password_hint" />
 
+        <TextView
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="10dp"
+            android:text="@string/profile_ca_label" />
+
+        <CheckBox
+            android:id="@+id/ca_auto"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:text="@string/profile_ca_auto_label" />
+
+        <CheckBox
+            android:id="@+id/ca_show_all"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="5dp"
+            android:text="@string/profile_ca_show_all" />
+
+        <Spinner
+            android:id="@+id/ca_spinner"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginBottom="5dp" />
+
     </LinearLayout>
 
 </ScrollView>

src/frontends/android/res/values/strings.xml

@@ -41,8 +41,13 @@
     <string name="profile_username_label">Username:</string>
     <string name="profile_password_label">Password:</string>
     <string name="profile_password_hint">(prompt when needed)</string>
+    <string name="profile_ca_label">CA certificate:</string>
+    <string name="profile_ca_auto_label">Select automatically</string>
+    <string name="profile_ca_show_all">Show all certificates</string>
     <!-- Warnings/Notifications in the details view -->
     <string name="alert_text_no_input_gateway">Please enter the gateway address here</string>
     <string name="alert_text_no_input_username">Please enter your username here</string>
+    <string name="alert_text_nocertfound_title">No CA certificate selected</string>
+    <string name="alert_text_nocertfound">Please select one or activate <i>Select automatically</i></string>
 
 </resources>