Remove assign field & add title, description in django

...ly/activity/templates/messages/email/ready_to_review.html

hypha/apply/api/v1/reminder/serializers.py

hypha/apply/api/v1/reminder/views.py

hypha/apply/funds/forms.py

hypha/apply/funds/migrations/0088_auto_20210423_1257.py

hypha/apply/funds/models/reminders.py

hypha/apply/funds/models/utils.py

.../funds/templates/funds/includes/create_reminder_form.html

...apply/funds/templates/funds/includes/reminders_block.html

...tatic_src/src/app/src/common/components/DateTime/index.js

...a/static_src/src/app/src/containers/DisplayPanel/index.js

...c/containers/ReminderContainer/components/ReminderList.js

...tic_src/src/app/src/containers/ReminderContainer/index.js

...src/src/app/src/containers/ReminderContainer/selectors.js

...atic_src/src/sass/apply/components/_reminder-sidebar.scss