Fixes #7304 - use dynflow for repository sync bulk actions
fixes #7621 - treat a nil minor OS version as empty string

other wise we will forever create operating systems in foreman
Merge pull request #4686 from jlsherrill/7621

fixes #7621 - treat a nil minor OS version as empty string
Merge pull request #4626 from iNecas/bulk-actions

Fixes #7304 - use dynflow for repository sync bulk actions