vct: simplify vct_system_purge_server
vct confine/sliver.lua: update SERVER_VERSION=0.8.7a0 (fix temporary ../interfaces/_/parent -> parent_name)
confine/*.lua: sliver interfaces
confine/*.lua: refactor ssl (towards sliver group_roles), recover from debug state, detect exceeded sliver_pub_ipv4_avail
confine/*.lua RestAPI sliver.nr
confine/*.lua refactor mgmt_net, user_roles, sliver interfaces handling
confine/tinc.lua cleanup
confine/tinc.lua refactoring
confine/*.lua: always use string keys internally
confine/system.lua: use lxc_template_path for template and exp_data downloads (safe space)
confine/*.lua: sliver exp_data_uri and _sha256 support
confine/*.lua: prepare for NODE_ID-SLICE_ID as SLIVER_ID url keys