Parse Ubuntu Ports more completely

Parse Ubuntu Ports more completely (fa41505f)

• Add riscv64 for impish
• Add security suites parsing to ports scanner
• Parse security suites separately
• Remove unused cron.d/100syncarchive_backports
• Change URLs for Ubuntu websites to use HTTPS for those that support it
• Port recent(ish) templates changes from master (mostly HTTP to HTTPS changes in Debian URLs, and some minor wording changes)
• Merge several upstream changes as best I can
  • merge commits: 779acd6c..396ffa26
  • cherry-picks accounted for by those merges: ed191ebd..ddf3d51b)

I think this MR fixes at least the following:

LP:1921951, LP:1866833, LP:1660938, LP:1816839, LP:1850906, LP:1876944

Signed-off-by: Daniel Llewellyn diddledan@ubuntu.com