[youtube] Use https: in more urls
[youtube] Encode the data when submitting the form for confirming the age

Needed on python 3
Merge remote-tracking branch 'origin/master' into merge
Fix ENOSPC (no space left on device) errors in the xattr PP.

Long descriptions not fitting into a FS block shouldn't error out the whole download

Signed-off-by: Orochimarufan <orochimarufan.x3@gmail.com>
Some additional metadata and a change in how the new filename is computed.

Signed-off-by: Orochimarufan <orochimarufan.x3@gmail.com>