Add 'flipper' and 'flipper-active_record' gems

We decide to move from Feature gem to Flipper gem to work with Feature
pattern, because it is more flexible and fits better to our needs.

It will allow us to handle both Beta and Rollout programs easily.

Co-authored-by: David Kang <dkang@suse.com>
Co-authored-by: Eduardo Navarro <enavarro@suse.com>
Co-authored-by: Henne Vogelsang <hvogel@opensuse.org>
Co-authored-by: Victor Pereira <vpereira@suse.com>