Add --enable-experimental configure option that allows to merge unstable
features or partially implemented features. This is supposed to help
features that need time to settle, tweak output or formatting and would
require constant rebases and would have limited exposure to users that
could provide feedback.
If this is enabled, the following may change without notice:
- the whole feature may disappear in the future
- new command names could change or relocate to other subcommands
- parameter names
- output formatting
- json output
Signed-off-by: David Sterba <dsterba@suse.com>