add fdholder and oneshotd service at start/stop of scandir. Be able to be session leader at start time for regular user

rename up/down subcommand to start/stop.

sanitize the graph of the system at every service parsing, remove -F option, force to use unsupervise command instead of -u at stop command

complete revamp of the 66-tree tool: interface change, add depends/requiredby and groups features. Allow to create a tree by a seed file

deprecates options -c|m|C|i at 66-enable and add option -I. Pass to the new configuration file format at ssexec_env.

add -c,-s,-V,-i options: -c change the symlink to target to the specified version. -s handle a specific version for command -L|V|e|r. -V displays available version. -i import extra configuration file from a version to another