We need to add a refreshRateSeconds property to the dashboard creation/update API, that gets stored as a property of a dashboard. The FE ticket will then apply this refresh rate to dashboards. It should also be possible for auto-refresh to be disabled

ATs:

• The refresh rate can be set when dashboards are created/updated
• REST API docs are updated

Hints:

• It might be some time before the FE work can be completed, so the API change shouldn't break anything if merged beforehand
• Existing dashboards should have auto-refresh disabled by default