[Tails-dev] [review'n'merge] obsolete stuff

Hello, I made a branch to remove obsolete stuff in
config/chroot_local-includes:
- very old doc about a laptop
- image unused since 1.0
- forum link in mksquashfs-excludes

Please review and merge.

Repo: https://git-tails.immerda.ch/xin/tails/
Branch: obsolete
Last Commit: 7ca0ef78187c2ad1681c6061274fb975d33c877f

Cheers.
xin