Siblings support and static package list generation

[Retropikzel]

This pull request does not have all the changes that the previous had, most notably the indentation changes. But also some functionality. Hopefully it is easier to review. Sorry for the previous messy pull request.

• Update repos using snow-chibi
• Statically generate package list
• Add search into package page
  • Package name as link messed with search so link is now in version
• Add atom feed of recent packages
  • Not in previous pull request
• Package page

Things mentioned in this #7 issue:

• Own page for packages so link to them does not download the file
• Licensen information
• Dependencies
  • Just immediate ones and static (no links) for now
• Signature
• Package size
  • This I could use some help for, it is now just bytes I think. What would be the best way to show it?

cron.sh uses snow-chibi to update repositories, this way the git siblings support is used from snow-chibi and that code does not need to be duplicated here. Repo files are passed to update.scm which generates package list, recent updates list and atom feed.

The cron.sh should be run periodically.