Add new regional/timeshift fields to Channel for additional variant info from the PA.
Add helper method related to countries to ChannelGroup.
Rework history output for simple model, and tidy up Simplification
 - Change channelNumber param to String
 - Add new ordering for channelNumbers. Ordered with non-zero prepended strings ordered in numerical order, followed by zero prepended strings, ordered in numerical order
Merge branch 'mbst-4019-ingest-pa-channel-data' into stage