Add migration to delete three RPA specialist sectors

This migration deletes three specialist sector tags if they exist. 
These have never been populated on GOV.UK, nor are they currently 
linked to, so it is not necessary to add redirects for these.
Merge pull request #171 from alphagov/remove-rpa-specialist-sectors-020614

Add migration to delete three RPA specialist sectors
Bump govuk_content_models to 11.2.0

To get the new manual and manual-section formats.
Merge pull request #172 from alphagov/bump-content-models

Bump govuk_content_models to 11.2.0
Fixes the display of pagination links
Bump govuk_content_models to 11.3.0

This fixes the validation issues that caused the migration to
fail.
Tag travel advice & business support content w/orgs

This adds a new migration which, when run, will tag every artefact with
a kind of ‘travel-advice’ with the FCO, and every artefact with a kind
of ‘business_support’ with BIS.
Merge pull request #174 from alphagov/tag-orgs-to-travel-advice-business-support

Tag travel advice and business support content with organisations
Merge pull request #173 from alphagov/fix-pagination-display

Fixes the display of pagination links
Correct the slugs and type in the RPA migration

The migration was intended to remove some unused tags, but had an
incorrect tag type and an incorrect slug, so failed to work in
production.

This migration was run on staging, but not on production, and the
database has been synced from production to staging since then.
Therefore, we're just leaving the migration date as it is.
Merge pull request #176 from alphagov/update-rpa-migration

Correct the slugs and type in the RPA migration