🔧 Pipe UDPServer and NetAddr proposal

• This is an UDPv4/v6 client/server wrapper in ccut, with a small address abstraction.
• Also moved the "WakeFd" pattern we use for threads in a class (found bugs in motion-lib on that one)

Some open questions:

• not sure about file names (everything in Net.hpp ?)
• not sure about class names : should we create a ccut::net namespace with ccut::net::Addr and ccut::net::UDPServer ?
• should UDPServer be renamed since it can act as server or client (maybe just UDPSocket) ?

I needed this to enhance the simulator part of fmc_mfe (will implement a really basic RPC using rapidyaml and this to directly access device memory), also open to other proposals.

Comments are welcome