This renames the case_log to lettings_log as everything we've written so
far has been geared towards lettings of social housing so it makes sense to
have the name describe this. This is also a precursor to adding in stuff for
sales logs (whatever shape that takes)
Co-authored-by: James Rose <james@jbpr.net>
* Add a non temp accommocation validation for vacancy reason
* Only show errors relevant to the page questions
* Add referral question/field
* Add validation for referrals and vacancy reasons
* change error message content