Added Sparkpost recognition

app/src/main/java/eu/faircode/email/MessageHelper.java

@@ -1700,6 +1700,10 @@ public class MessageHelper {
         if (!TextUtils.isEmpty(sendinblue))
             return "sendinblue";
 
+        String sparkpost = imessage.getHeader("X-MSFBL", null);
+        if (!TextUtils.isEmpty(sparkpost))
+            return "sparkpost";
+
         return null;
     }
 

app/src/main/res/drawable/infra_sparkpost.xml

@@ -0,0 +1,12 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="64dp"
+    android:height="64dp"
+    android:viewportWidth="64"
+    android:viewportHeight="63.999996">
+  <path
+      android:pathData="m31.6628,57.5979c-5.7398,-0 -10.3937,-4.6534 -10.3937,-10.3935 0,-5.7403 4.6538,-10.3937 10.3937,-10.3937 5.7403,-0 10.3937,4.6534 10.3937,10.3937 0,5.74 -4.6534,10.3935 -10.3937,10.3935zM42.2069,24.9299c-3.305,2.4933 -3.9445,6.893 -4.042,9.867 -5.2236,-6.0409 9.674,-23.8132 -7.2545,-34.7969C41.3892,13.5611 16,26.8936 16,46.8716 16,54.7028 20.8934,61.6044 31.6415,64 42.1847,61.7552 47.387,54.7028 47.387,46.8718c0,-11.6764 -7.2693,-15.5829 -5.18,-21.9419"
+      android:strokeWidth="0.04949844"
+      android:fillColor="#f15022"
+      android:strokeColor="#00000000"
+      android:fillType="nonZero"/>
+</vector>

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

@@ -1815,6 +1815,7 @@
     <string name="infra_salesforce" translatable="false">Salesforce</string>
     <string name="infra_sendgrid" translatable="false">SendGrid</string>
     <string name="infra_sendinblue" translatable="false">Sendinblue</string>
+    <string name="infra_sparkpost" translatable="false">Sparkpost</string>
 
     <string-array name="pollIntervalNames">
         <item>Always</item>