When new partners are added to a submission, notify the applicant and the added partners.

opentech/apply/activity/messaging.py

opentech/apply/activity/migrations/0023_notify_partners.py

opentech/apply/activity/options.py

opentech/apply/activity/templates/messages/email/base.html

...y/templates/messages/email/partners_update_applicant.html

...ity/templates/messages/email/partners_update_partner.html

...s/templates/funds/applicationsubmission_admin_detail.html

opentech/apply/funds/views.py