Increase surge model alert period to 37 hours

This should allow us to catch a single collector failure.

https://www.pivotaltracker.com/story/show/78027064 [Delivers #78027064]
Clean up after tests
Merge pull request #105 from sealevelresearch/increase-surge-model-alert-time

Increase surge model alert period to 37 hours
Auto-reload API status page

So that you can just leave it open in a browser.
Merge pull request #106 from sealevelresearch/auto-reload-status-endpoint

Auto-reload API status page
Add an HTML title to the API status page

So it's visible in a tab in the browser.
Change surge model alerts from 37 to 36 hours

Logic fix: In normal operation we expect there to be around 36.5 to 37
hours of surge predicitions. We should alert on thw *lower* of these -
ie if there are less than 36 hours, not 37.

[Delivers #81663554]
Merge pull request #107 from sealevelresearch/api-status-html-title

Add an HTML title to the API status page
More post-test cleanups

As SurgePredictions seems to be interfering with each other across
different test suites :S
Merge pull request #108 from sealevelresearch/surge-alerts-36-hours

Change surge model alerts from 37 to 36 hours
(Mostly) delete old surge-model-converter app

- Migration to kill off the database columns (ModelLocation)
- Delete basically all the code.

Note that you have to keep a skeleton app with the `migrations` and
`models` directory (but without any models) in order for the
`DeleteMigration` migration to be recognised. ie if you just delete the
app, its data would hang around in the database forever.

In the future (once all databases have been migrated) we can delete the
app completely and remove it from `INSTALLED_APPS`

https://www.pivotaltracker.com/story/show/81100150 [Delivers #81100150]
Merge pull request #109 from sealevelresearch/kill-surge-model-converter-app

(Mostly) delete old surge-model-converter app
WIP