This PR removes the static-openssl feature. If necessary, this features can
be invoked by selecting openssl/vendored directly.
The PR also removes building and testing with default features from the CI
workflow. The only difference between default and all features currently is
rta which is deprecated and will be removed, anyway.
This PR now also fixes a few issues in krillc config simple and the post
install scripts for Debian and RPM packages.
* Support "prepare-upgrade" through "krillup" binary.
* Package the new `krillup` binary and man page into a separate DEB/RPM.
* Also switches to building in a Rocky Linux container due to repeated CentOS 8 vault repo timeouts.
* Mention correct config file location on CLI help.
* Remove incorrect reference to non-existent help subcommand for krillup.
* Add locking to upgrade process.
Co-authored-by: Ximon Eighteen <3304436+ximon18@users.noreply.github.com>
