PaFeaturesProcessor uses Ordering using Broadcast.TO_TRANSMISSION_TIME
Refactor PA Featured Content updater

Instead of creating a new `PaFeaturesProcessor` for each run of the task
it is passed as a collaborator with a `prepareUpdate` method.
Include tomorrow's features picks in today's group
Merge pull request #324 from atlasapi/mbst-6729-pa-features-tomorrow

MBST-6729 PA Features includes tomorrow's picks
Warn about unrecognised service providers (as we don't know how to create an alias for them), but don't throw
an exception that would cause the ingest of the channel to fail.
Ensure known aliases on channels are correctly merged.
Merge branch 'cope-with-unrecognised-service-providers' into stage