Update aruba timeout to use config block
Created by: bjfish
This updates to be similar to: https://github.com/rspec/rspec-mocks/blob/4be625e322ed1da7607ecab0e838efd9453ac0c6/features/support/env.rb#L4-L10
The current usage @aruba_timeout_seconds
appears to be deprecated:
https://github.com/cucumber/aruba/blob/1c6bc8731891692f5064fcfd1ff8a885c23298a6/CHANGELOG.md#080pre