Add optional note field to Facility

- Allows you to send whatever text you want to clients
- Responsibility on admins once again

Closes #63
3 jobs for 63-facility-note in 1 minute and 35 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #3785
whats-open-py2.7

00:01:31

passed #3786
whats-open-py3.5

00:01:31

passed #3787
whats-open-py3.6

00:01:35