Added multiple selection

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

@@ -0,0 +1,25 @@
+package eu.faircode.email;
+
+import androidx.annotation.Nullable;
+import androidx.recyclerview.selection.ItemDetailsLookup;
+
+public class ItemDetailsMessage extends ItemDetailsLookup.ItemDetails<Long> {
+    private int pos;
+    private Long key;
+
+    ItemDetailsMessage(int pos, Long id) {
+        this.pos = pos;
+        this.key = id;
+    }
+
+    @Override
+    public int getPosition() {
+        return pos;
+    }
+
+    @Nullable
+    @Override
+    public Long getSelectionKey() {
+        return key;
+    }
+}