Made Group import work

It was tricky since Creating a user also creates the group. This led to
confusion during development of import.
Change the duplication processing on Expense

Do a record lookup first then do an update if required, this way we
minimize writes which can be an issue on databases like sqlite
Created required.rb file to easily require all legacy models in rails
console
Fixed some legacy import models, added LegacyGroupMember
Change import to set id of new records

Added more imports
Added run times to import_data task
Added counts to screen output of validate methods