remove httmock

as it causes tests to hang outside of the dev vm
Simplify the status endpoint and return status

If one of our deps isn't ok then we should be sending a 5xx status.

There was a lot of dupe between the two status checks so I've pulled it
out into a function.

The status of the admin app is now dependant on the status of its
dependencies.
Tests for grouping by data set group

this may not be the final place for them but it will do for now
Working group by group method
Add tests for happy path data set list

This got removed in extracting out the helpers and removing duplicate
tests
Group by data group - amend template and use function in route
Merge pull request #37 from alphagov/group-by-group

Group by group
Merge pull request #35 from alphagov/no-httmock

remove httmock
Merge pull request #36 from alphagov/improve-status-endpoint

Simplify the status endpoint and return status
Remove group from data set list
Merge pull request #38 from alphagov/remove-group-from-list

Remove group from data set list
Ul should be in li, this will also make the smoke tests simpler
Merge pull request #39 from alphagov/remove-group-from-list

Ul should be in li, this will also make the smoke tests simpler
Rearrange __init__.py so common code is local

I've moved all the importing (bar the loading of routes) into one place
as well as batching up the setting of app information.
Add Sentry to admin app

We are adding this so we have a central place we can go and look at our
exceptions. This will only sent stuff back to sentry when the SETNRY_DSN
is set, but shouldn't interrupt our app if it isn't.
Merge pull request #40 from alphagov/add-sentry-tracking

Add sentry tracking
Remove redis session

Managing token caching and reauth has been moved back into stagecraft to
avoid a call back to signon for every request there.
Log user out on 401 not 403

Unauthorized and Forbidden have been split out in stagecraft now. We
should not sign the user out if they do not have sufficient permissions.