TAPI: Test API for configuration nodes

Test scenarios can use functions exported by Configurator API directly: API: Configurator, but there are high level interfaces that simplify access to some parts of configuration tree.

ARL table configuration
Agent namespaces configuration
Agents, namespaces and interfaces relations
Bonding and bridging configuration
CPU topology configuration of Test Agents
Command monitor TAPI
DHCP Server configuration
DUT serial console access
Environment variables configuration
Ethernet PHY configuration
Ethernet interface features configuration
IP rules configuration
IPv6 specific configuration
Kernel modules configuration
L2TP configuration
Local subtree access
Manipulation of network address pools
NTP daemon configuration
Neighbour table configuration
Network Base configuration
Network Emulator configuration
Network Interface configuration
Network Switch configuration
Network sniffers configuration
Network statistics access
Network topology configuration of Test Agents
PPPoE Server configuration
Processes configuration
Queuing Discipline configuration
tc qdisc TBF configuration
Routing Table configuration
Serial console parsers configuration
Solarflare PTP daemon configuration
System parameters configuration
TA system options configuration (OBSOLETE)
Test API to handle a cache
VTund configuration
Virtual machines configuration
XEN configuration
iptables configuration