These are more convenient and safer than the manual vtables we have in
the fuzzer support code. We can override individual member functions,
and C++ will take care of correctly casting and offsetting this-pointers
when needed.
Every use of this function needs to allocate the same buffer. None of
the callers uses a differently sized buffer, so we might as well put it
in a struct and have the type checker prove the buffer size is correct.
Also rename `ip_ntoa` to `net_ip_ntoa` to avoid clashes with ESP-IDF
system libraries which define this function as well.
The brackets serve no purpose and make us do extra string
parsing when using the output for other things
Also removed a useless call to ip_ntoa in LAN_discovery.c
