android: Use separate activity to control VPN connections

This way we don't have to open the main window, but only show a dialog
if necessary (or nothing in many cases).

src/frontends/android/app/src/main/AndroidManifest.xml

@@ -36,10 +36,21 @@
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
+        </activity>
+        <activity
+            android:name=".ui.VpnProfileControlActivity"
+            android:theme="@style/TransparentActivity"
+            android:taskAffinity=""
+            android:excludeFromRecents="true"
+            android:launchMode="singleTask" >
             <intent-filter>
                 <action android:name="org.strongswan.android.action.START_PROFILE" />
                 <category android:name="android.intent.category.DEFAULT" />
             </intent-filter>
+            <intent-filter>
+                <action android:name="org.strongswan.android.action.DISCONNECT" />
+                <category android:name="android.intent.category.DEFAULT" />
+            </intent-filter>
         </activity>
         <activity
             android:name=".ui.VpnProfileDetailActivity" >