remove use of s6-rc. Split sanitize_system to new function. Revamp clone feature. Do not handle anymore backup directory at clone time. Pass to new graph_matrix_get_edge_g_sorted_sa() and graph_matrix_get_edge_g_sa() functions interface

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

[WIP] Implementation of new graph API. Implements seed file features. Use new interface of sastr_dir_get.