* Adds a new component server/nic_uplink that forwards packets unmodified
between one Uplink session at one side and potentially multiple Nic sessions
at the other side.
* Adds a new run script nic_uplink.run that does a basic test with multiple
Nic clients on this component and adds it to the autopilot list.
* Adds a new depot recipe src/nic_uplink for this component.
* Adds a new depot recipe pkg/pc_nic for deploying the pc_nic_driver together
with a nic_uplink server. This allows for raw access to the network connected
to the Nic of the system in contrast to the commonly used routed and NAT'd
access via NIC router. That said, it enables the use of network protocols
not yet supported by the NIC router at the cost of less protection.
Ref #4966
