addurl, importfeed: Added --no-raw option

addurl, importfeed: Added --no-raw option

Forces eg, download with youtube-dl without falling back to raw download.

Since youtube-dl failing due to an url not being supported is difficult to
distinguish from it failing due to being blocked in some way, this can be
useful to avoid the fallback of git-annex downloading the raw web page and
adding that.

Since --raw also prevents using special remotes, --no-raw also
allows special remote downloads. Although it's always possible that some
special remote may claim an url and fall back to raw download of the
content, which --no-raw cannot prevent.

Sponsored-by: Boyd Stephen Smith Jr. on Patreon