Remove middleman-search from Jenkins
Remove middleman-search from Jenkins

This tool is no longer being built by Jenkins [1] (it didn't actually have a
test suite so was always a bit of an odd-fit here)

[1]: https://github.com/alphagov/middleman-search/pull/10

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet