Line up UK Hydrographic Office title with Whitehall
Normalise sites YAML

YAML rewritten according to Psych's idea of canonical

- removes indentation
- removes --- from end of files
Script to add Whitehall slugs (one-shot)
Add Whitehall slug for the organisation which owns each site
Merge pull request #422 from alphagov/add-whitehall-slugs

Add whitehall slugs