Add redirects for health-check paths
Add redirects for health-check paths

These are currently 404ing as Icinga is linking to them. There is a PR
open to fix them: https://github.com/alphagov/govuk-puppet/pull/5985

alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs