Adding MHRA Pharma Specialist Sectors

Relates to https://www.pivotaltracker.com/story/show/67287128.
Specialist sectors for the MHRA Pharmaceutical industry.
Merge pull request #141 from alphagov/add-mhra-pharma-sector

Adding MHRA Pharma Specialist Sectors

https://www.pivotaltracker.com/story/show/67287128