0.0.99.1

Overview of changes

• Add deprecation notices to the POSIX shell implementation
• Add test for the new --distro option
• Drop the FGC namespace from the fedora-toolbox images
• Fix miscellaneous issues pointed out by https://www.shellcheck.net/
• Handle hosts with /etc/localtime as absolute symlink
• Improve README.md
• Improve the Zuul configuration
• Mount /mnt only if it is available
• Refactor the system tests, and use bats-assert and bats-support
• Test that sudo doesn't require a password
• Update the manuals