OC2:R native ICMP module

The Java ICMP functions don't work on some operating systems without admin/root, so a native library is required.

Platform support:

Officially supported:

• Windows x86_64 and aarch64
• GNU/Linux x86_64 and aarch64
• macOS x86_64 and aarch64

Not officially supported, but should still build:

• Any Linux
• Any macOS
• Any Windows