svtplay: Fix import of HLS fetcher
Break out progress() to svtplay.output module

Now it is very clear that progressbar() duplicates an existing function. But
obsoleting one or the other is work for the future.
Breakout http fetcher to own module
hds: import progress_stream from svtplay.output
Breakout rtmp fetcher to own module
Break out HLS fetcher to module
svtplay.output: don't import log (not used)
HBO: Add options argument to get()
Add minimal set of imports for services to work
Clean up svtplay_dl script (remove moved code)