Replace channels and volumes with volumes/channel

Now that we’re a more mature platform we don’t care so much about the
load that one service might put on our platform.

We do care about intended volumes for two reasons:
- modelling the benefits that services get from using Notify
- managing stocks of envelopes (while our letter volumes are small
  enough that they could be skewed by one new service)

Changing to the ‘how many per year’ question also has the benefit of
mapping directly to the data we store in the ‘beta partners’
spreadsheet.

app/main/views/service_settings.py

@@ -14,7 +14,6 @@ from flask import (
 from flask_login import current_user, login_required
 from notifications_python_client.errors import HTTPError
 from notifications_utils.field import Field
-from notifications_utils.formatters import formatted_list
 
 from app import (
     billing_api_client,
@@ -217,13 +216,14 @@ def submit_request_to_go_live(service_id):
         zendesk_client.create_ticket(
             subject='Request to go live - {}'.format(current_service.name),
             message=(
-                'Service: {}\n'
-                '{}\n'
+                'Service: {service_name}\n'
+                '{service_dashboard}\n'
                 '\n---'
-                '\nOrganisation type: {}'
-                '\nAgreement signed: {}'
-                '\nChannel: {}\nStart date: {}\nStart volume: {}'
-                '\nPeak volume: {}'
+                '\nOrganisation type: {organisation_type}'
+                '\nAgreement signed: {agreement}'
+                '\nEmails in next year: {volume_email}'
+                '\nText messages in next year: {volume_sms}'
+                '\nLetters in next year: {volume_letter}'
                 '\n'
                 '\n---'
                 '\n'
@@ -233,23 +233,20 @@ def submit_request_to_go_live(service_id):
                 '{user_name}\t'
                 '{user_email}\t'
                 '-\t'
-                '{date}'
+                '{date}\t'
+                '{volume_sms}\t'
+                '{volume_email}\t'
+                '{volume_letter}'
             ).format(
-                current_service.name,
-                url_for('main.service_dashboard', service_id=current_service.id, _external=True),
-                current_service.organisation_type,
-                AgreementInfo.from_current_user().as_human_readable,
-                formatted_list(filter(None, (
-                    'email' if form.channel_email.data else None,
-                    'text messages' if form.channel_sms.data else None,
-                    'letters' if form.channel_letter.data else None,
-                )), before_each='', after_each=''),
-                form.start_date.data,
-                form.start_volume.data,
-                form.peak_volume.data,
+                service_name=current_service.name,
+                service_dashboard=url_for('main.service_dashboard', service_id=current_service.id, _external=True),
+                organisation_type=current_service.organisation_type,
+                agreement=AgreementInfo.from_current_user().as_human_readable,
+                volume_email=form.volume_email.data,
+                volume_sms=form.volume_sms.data,
+                volume_letter=form.volume_letter.data,
                 service_id=current_service.id,
                 organisation=AgreementInfo.from_current_user().owner,
-                service_name=current_service.name,
                 user_name=current_user.name,
                 user_email=current_user.email_address,
                 date=datetime.now(tz=pytz.timezone('Europe/London')).strftime('%d/%m/%Y'),