Further improvements

[rhaschke]

Speed

• Use eatmydata?
• Use layered chroot: base (ro) - populated (rw) - sbuild (volatile)
  This will allow to enable populated as default and fallback to base on failure automatically.
  For example, gazebo requiring ogre 9.0 conflicts with rviz using ogre 12.x
• Skip a package if its dependencies are not available
• Replace vcs --shallow with partial clone

TODO

• Check and fix security using eval: Only expand vars, but don't allow subshell execution?
  https://www.baeldung.com/linux/bash-safe-use-eval
• Fix ici_filter usage
  • Output of ici_apt_install is not filtered?!
  • Use ici_quiet for bloom-generate and sbuild? Optionally, create full output again.
• Replace deprecated apt-key.
  https://askubuntu.com/questions/1286545/what-commands-exactly-should-replace-the-deprecated-apt-key
  https://wiki.debian.org/SecureApt#How_to_find_and_add_a_key

Features

• Implement CONTENT_MODE=newer: only keep newest package files
• Allow selection of (additional) files to deploy: DEPLOY_FILES=".dsc *.ddeb changes"
• Maintain the database of actually build sources (with commit sha) in a sources.repos file on the deploy repository.
  • Optionally? use that version when rebuilding downstream packages in the repo
  • python helper to add, query, etc that database.
• Merge remote.yaml and local.yaml into ros-$ROS_DISTRO.yaml?
• Create docker image for use in CI builds (e.g. MoveIt, MTC)
• Deploy to reprepro
  • Setup a TF-hosted webserver for reprepro
    • Generate keys for https and to sign .debs: https://letsencrypt.org/de/getting-started
• Support rosdistro package index for ROS_SOURCES
  This should allow building existing ROS distros on custom debian distros