Cleaning, better naming.

Adding NGOptRW, presumably better than NGOpt for real-world problems.
Adding YAPBBOB, with a parameter regulating YABBOB-like problems so that the distribution of the optimum is less rotationally invariant.
Making some dependencies optional because running was becoming too complicated.
There should be no breaking change.
Adding constrained counterparts of YABBOB: yapenbbob (a few constraints), yaonepenbbob (single constraint), yamegapenbbob (many constraints).
Improvements in the photonics benchmarks.
Externalizing CompilerGym.
Making some tests less flaky.
Adding Simulated annealing and Tabu search.
Adding the NLOPT library.
Making the code more robust to Gym environments.
Adding smoothness operators for discrete optimization.