Improvements to form fields

Fix Section Header field render issue

Remove js-hidden class from wrapped block inside the group fields

Upgrade Django bleach to 3.x and bleach to 5.x

Align the ordering of the filterns with the columns on submission table

Fix Group field's bugs

Check if related page exist before trying to render it.

Update to Django 3.2.14.

Move confirmation mail template to where all other mail templates are…

Remove period and add missing link in Slack templates

Integrate django-slack for direct slack messaging from hypha

Update submit time when applicant submit a submission

Move confirmation mail template to where all other mail templates are. Make messages names a bit more clear.