Prioritize web app manifest favicons

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

@@ -712,12 +712,14 @@ public class ContactInfo {
                                 String src = jicon.optString("src");
                                 String sizes = jicon.optString("sizes", "");
                                 String type = jicon.optString("type", "");
+                                String purpose = jicon.optString("purpose", "");
                                 if (!TextUtils.isEmpty(src)) {
                                     Element img = doc.createElement("link")
                                             .attr("rel", "manifest")
                                             .attr("href", src)
                                             .attr("sizes", sizes)
-                                            .attr("type", type);
+                                            .attr("type", type)
+                                            .attr("purpose", purpose);
                                     imgs.add(img);
                                 }
                             }
@@ -849,6 +851,9 @@ public class ContactInfo {
                 .trim();
         String type = img.attr("type")
                 .trim();
+        String purpose = img.attr("purpose")
+                .toLowerCase(Locale.ROOT)
+                .trim();
 
         int order = 0;
         if ("link".equals(img.tagName()))
@@ -856,12 +861,15 @@ public class ContactInfo {
 
         boolean isIco = (href.endsWith(".ico") || "image/x-icon".equals(type));
         boolean isSvg = (href.endsWith(".svg") || "image/svg+xml".equals(type));
-        boolean isMask = ("mask-icon".equals(rel) || img.hasAttr("mask"));
+        boolean isMask = ("mask-icon".equals(rel) || img.hasAttr("mask") || purpose.contains("mask"));
+        boolean isMonochrome = purpose.contains("monochrome");
 
-        if (isMask)
+        if (isMask || isMonochrome)
             order = -10; // Safari: "mask-icon"
         else if ("icon".equals(rel) && !isIco)
             order += 20;
+        else if ("manifest".equals(rel))
+            order += 20;
         else if ("apple-touch-icon".equals(rel) ||
                 "apple-touch-icon-precomposed".equals(rel)) {
             // "apple-touch-startup-image"