Change web scraping with now-obsolete metadata extraction code

Only applies if XML::Simple is missing or --playlist-metadata used.

Revert to scraping by default for tv programme versions.  Many CBBC
programmes, and possibly others, lack XML or JSON playlists, so
scraping is the only option.  Use --no-scrape-versions to prevent.

Remove scraping for series/episode numbers - slow and unreliable.