Forward person when a programming group is created with them

Further, we remove the "check invitation" button and extract some methods to our new ProgrammingGroups object in JavaScript.

Co-authored-by: Sebastian Serth <Sebastian.Serth@hpi.de>

app/views/programming_groups/_form.html.slim

@@ -6,4 +6,3 @@
     /.help-block.form-text = t('.hints.programming_partner_ids')
   .actions.mb-0
     = render('shared/submit_button', f: f, object: @programming_group)
-    a.btn.btn-secondary.float-end href=new_exercise_programming_group_path(@exercise) == t('programming_groups.new.check_invitation')

app/views/programming_groups/new.html.slim

@@ -1,5 +1,5 @@
 h1 = t('programming_groups.new.create_programming_pair')
-.row
+#matching.row data-exercise-id=@exercise.id
   .col-md-6
     p
       => t('programming_groups.new.own_user_id')