Merge pull request #448 from OpenTechFund/feature/286-add-applicant-communication

opentech/apply/activity/forms.py

opentech/apply/activity/messaging.py

...tech/apply/activity/migrations/0009_add_private_option.py

opentech/apply/activity/models.py

...ply/activity/templates/activity/include/listing_base.html

opentech/static_src/src/sass/apply/components/_feed.scss

opentech/static_src/src/sass/apply/components/_grid.scss

opentech/static_src/src/sass/apply/components/_icon.scss

opentech/static_src/src/sass/apply/components/_tabs.scss

opentech/templates/includes/sprites.html