Dup role name to avoid appending to original name

www.agileplannerapp.com/boards/173808/cards/6384

the role variable was storing a reference to the
role name string to which appointment date ranges
were being appended. hence for every subsequent
role appointment, the previous appointment date
ranges were also being shown.
Data migration to clear related cache
Migration for updating parent_tag for 'housing' detailed guides

The housing tag is being replaced with housing-local-services, this updates the detailed guides
Merge pull request #1789 from alphagov/fix-for-role-name-select

Fix for ministerial role name select labels
Merge pull request #1796 from alphagov/renaming_housing_parent_tags

Migration for updating parent_tag for 'housing' detailed guides