Search should ignore dashes and spaces when searching

e.g. SW1A1AA vs SW1A 1AA and ref 1967966543 vs 19-6796-6543
handle case when no postcode/reference
handle split case scenarios for new search_field
Merge pull request #263 from ministryofjustice/feature/ignore-dashes-spaces-in-search

Search should ignore dashes and spaces when searching