This commit includes several new functions to support sending custom
raw Ethernet packets. This includes methods for retrieving
MAC addresses, sending empty EtherCAT packets, and sending
arbitrary raw packets with specified types and destinations.
These functions are primarily intended for testing purposes
and rely on the `send-raw-packet-downstream` command provided
by NetworkStack.
Test: atest NetworkStaticLibHostPythonTests
Bug: 335368434
Change-Id: Iae7879bf92e1dda8fbd32b92ff166e82c87593c7
Junyu Lai
commited