avatars: refactor avatar generation

- removes old default avatar
- removes the '?' avatars
- corrects color generation

Change-Id: I722715aaa7657566ecc525dacd74c62e3712f1fa
diff --git a/contactrequestwidget.ui b/contactrequestwidget.ui
index 6c127bf..3471b8b 100644
--- a/contactrequestwidget.ui
+++ b/contactrequestwidget.ui
@@ -69,7 +69,7 @@
       <string/>
      </property>
      <property name="pixmap">
-      <pixmap resource="ressources.qrc">:/images/user/btn-default-userpic.svg</pixmap>
+      <pixmap resource="ressources.qrc">:/images/default-avatar-overlay.svg</pixmap>
      </property>
      <property name="scaledContents">
       <bool>true</bool>