Allow for a Notes section for the Splash Page

[raymondberg]

We'd love to have a small message that says

Text messages go straight to our on-call team and preserve your anonymity. Email goes to the full board for review.

This issue would be to create a notes or public_description or similar field to let groups call out small specifics of their response process.

The goal isn't for hosted documentation, just something on par with a Twitter account description.