Reimplement core::uuid_generate() using libuuid

[gavv]

We have simple implementation of UUID generation using random numbers. It would be great to have alternative optional implementation using libuuid from util-linux package.

Our implementation is portable but unsophisticated. It blindly generates random UUID no matter where it's running and what's the quality of PRNG. libuuid, on the other hand, is capable to check system capabilities: if high-quality random generator is available, it will use it, otherwise it will fallback to using low-level system information like MAC address and system time. It will also employ uuidd if it's present on system.

Steps:

• Add libuuid to build scripts (build-3rdparty.py, 3rdparty/Sconscript). Add --disable-libuuid to SConstruct. If the option is given, enable target_nouuid target directory, otherwise enable target_libuuid.

  Basically you can replicate what have been done in this commit to add OpenSSL (you can ignore openssl_get_platform() function, it's OpenSSL-specific).

• Move existing implementation from roc_core to roc_core/target_nouuid target directory.

• Add new implementation to roc_core/target_libuuid using libuuid.

• Add simple test that will pass for both implementations.

Related docs:

• https://roc-streaming.org/toolkit/docs/development/continuous_integration.html
• https://roc-streaming.org/toolkit/docs/building/developer_cookbook.html

[nolan-veed]

This one is right up my street. I'll do it.