Feature vnet log aggregation

output example:
```
% bin/dev-spec run
.....
.....
result: success

% find log/dev/current/ -type f
log/dev/current/secg/vna5.log
log/dev/current/secg/vnmgr.log
log/dev/current/secg/webapi.log
log/dev/current/secg/vna3.log
log/dev/current/secg/vna2.log
log/dev/current/secg/vna1.log
log/dev/current/secg/vna4.log
log/dev/current/router_p2v/vna5.log
log/dev/current/router_p2v/vnmgr.log
log/dev/current/router_p2v/webapi.log
log/dev/current/router_p2v/vna3.log
log/dev/current/router_p2v/vna2.log
log/dev/current/router_p2v/vna1.log
log/dev/current/router_p2v/vna4.log
log/dev/current/service/vna5.log
log/dev/current/service/vnmgr.log
log/dev/current/service/webapi.log
log/dev/current/service/vna3.log
log/dev/current/service/vna2.log
log/dev/current/service/vna1.log
log/dev/current/service/vna4.log
log/dev/current/edge_esxi/vna5.log
log/dev/current/edge_esxi/vnmgr.log
log/dev/current/edge_esxi/webapi.log
log/dev/current/edge_esxi/vna3.log
log/dev/current/edge_esxi/vna2.log
log/dev/current/edge_esxi/vna1.log
log/dev/current/edge_esxi/vna4.log
log/dev/current/secg_reference/vna5.log
log/dev/current/secg_reference/vnmgr.log
log/dev/current/secg_reference/webapi.log
log/dev/current/secg_reference/vna3.log
log/dev/current/secg_reference/vna2.log
log/dev/current/secg_reference/vna1.log
log/dev/current/secg_reference/vna4.log
log/dev/current/router_v2v/vna5.log
log/dev/current/router_v2v/vnmgr.log
log/dev/current/router_v2v/webapi.log
log/dev/current/router_v2v/vna3.log
log/dev/current/router_v2v/vna2.log
log/dev/current/router_v2v/vna1.log
log/dev/current/router_v2v/vna4.log
log/dev/current/simple/vna5.log
log/dev/current/simple/vnmgr.log
log/dev/current/simple/webapi.log
log/dev/current/simple/vna3.log
log/dev/current/simple/vna2.log
log/dev/current/simple/vna1.log
log/dev/current/simple/vna4.log
log/dev/current/event/vna5.log
log/dev/current/event/vnmgr.log
log/dev/current/event/webapi.log
log/dev/current/event/vna3.log
log/dev/current/event/vna2.log
log/dev/current/event/vna1.log
log/dev/current/event/vna4.log
```