tooling box: added nginx + polished bash scripts and environment

- add installation method for nginx sites, morty and filtron
- clean up PUBLIC_URL environment in and outside of containers
- clean up comand lines
- handle uWSGI quirks on fedora (emperor mode)
- handle Python quirks on debian (there is no 'python' command anymore)
- lib.sh: add die and die_caller functions
- lxc_suite_install_info is now a function
- lint: shellcheck

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>