Merge branch 'avatar-of-teachers-' into 'master'

Load avatar of affected teachers

See merge request !392

aleksis/apps/chronos/frontend/components/substitutions.graphql

@@ -2,6 +2,7 @@ query substitutionsForDate($date: Date!) {
   items: substitutionsForDate(date: $date) {
     affectedTeachers {
       id
+      avatarContentUrl
       shortName
       fullName
     }