HLS to DASH (special mode - take existing HLS feed and repackage as DASH)

[cannonbeach]

I've had a couple of requests for this but haven't had a chance to add this mode. This would take an existing HLS feed and then repackage it into a DASH feed.
There are two ways this can be done:

• simple repackage of all ABR streams - 1:1
• repackage the highest resolution stream and then locally generate the smaller resolutions from that at the edge (which involves some transcoding)
  these cases can get a bit complicated when ad insertion is involved, so maybe the ad insertion should happen downstream from this
  (Possibly an option for an oppose mode to this as well - DASH to HLS)