Skip validations while duplicating editions

www.agileplannerapp.com/boards/173808/cards/4296

we have added a new validation for checking
invalid links in editions. currently, editors
are unable to create drafts from published
editions having invalid links because this
validation fails.

this proposed change will skip validations
while duplicating editions. if there are
existing published editions which are deemed
invalid because of new validation rules, then
editors should be able to create a new edition
and rectify those validation errors.

govuk_content_models was updated to remove
unnecessary edition save calls which caused
validations to happen multiple times when an
edition was duplicated, which was needed to
support this change:

https://github.com/alphagov/govuk_content_models/pull/187
https://github.com/alphagov/govuk_content_models/pull/186
Merge pull request #225 from alphagov/bump-content-models

Skip validations while duplicating editions
Migrate locations to Mapit areas.

Finds the regional Mapit area identifiers for business support locations
and populates the areas array with them.
Merge pull request #226 from alphagov/add_bsf_locations_to_areas_migration

Migrate locations to Mapit areas.
Add a stub health check controller and response.
Add functional tests for healthcheck controller.

And a status field so there's something to test.
Add a check for the scheduled publishing queue.

From time to time, an item will be scheduled for publishing, but the
code to add it to the Sidekiq queue will fail. We should have monitoring
for when this happens, so we can give it a nudge.
Recover from Mongo/Redis failures in healthcheck.

If the health check returns a non-200 response, our monitoring
currently treats this as the entire app being broken, so we should
recover from errors wherever possible.