This commit adds two new sections to the dashboard
1. A banner telling you about trial mode, including a count of how many messages
you have left today, which is a restriction of trial mode
2. Panels with counts of how many emails and text messages have been sent in a
day, plus the failure rates for each
It does **not**:
- link through to any further information about what trial mode is (coming
later)
- link through to pages for the failure rates (coming later)
- change the ‘recent jobs’ section to ‘recent notifications’
