Implement LuiActivity for settings integration

For full integration, we would have to implement EuiccService, but that
would mean refactoring everything every time with Android updates and
giving up the ability to manage non-embedded eUICC cards. For now, I
think having our own UI is the best plan of action. EuiccService is only
useful with carrier apps anyway and those likely require Google
services.

app/src/main/AndroidManifest.xml

@@ -29,6 +29,17 @@
             </intent-filter>
         </activity>
 
+        <activity android:name=".ui.LuiActivity"
+            android:exported="true"
+            android:permission="android.permission.BIND_EUICC_SERVICE">
+            <intent-filter android:priority="100">
+                <action android:name="android.service.euicc.action.MANAGE_EMBEDDED_SUBSCRIPTIONS" />
+                <action android:name="android.service.euicc.action.PROVISION_EMBEDDED_SUBSCRIPTION" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <category android:name="android.service.euicc.category.EUICC_UI" />
+            </intent-filter>
+        </activity>
+
         <activity
             android:name="com.journeyapps.barcodescanner.CaptureActivity"
             android:screenOrientation="fullSensor"

app/src/main/java/im/angry/openeuicc/ui/LuiActivity.kt

@@ -0,0 +1,12 @@
+package im.angry.openeuicc.ui
+
+import android.content.Intent
+import androidx.appcompat.app.AppCompatActivity
+
+class LuiActivity : AppCompatActivity() {
+    override fun onStart() {
+        super.onStart()
+        startActivity(Intent(this, MainActivity::class.java))
+        finish()
+    }
+}