Add a CLI tool to handle PHY sniffing, sending, scripting

[virtualabs]

Add a tool named phy-tool that provides an interactive shell and commands to sniff, scan and send PHY packets.

The interactive shell provides the following commands:

• sniff to start sniffing with the current PHY configuration
• mod to select a specific modulation scheme to use
• freq to select a specific frequency
• send to send a packet using the current PHY configuration
• trigger to wait for a packet matching a specific pattern to be received
• scan to scan a range of frequencies at a specific speed and show sniffed packets

This tool supports scripting and can be feed with a specific script.

This tool supports the piping mechanism when not used in interactive mode.