Add a new crate gpqa for assessing optimizer GP quality

[relf]

This PR introduces a new binary crate gpqa allowing to assess the qulity of Gpx surrogate saved in binary file or the GP surrogates created by the Egor optimizer.
At the moment, initial/last GP surrogates generated by Egor can be stored in egor_initial_gp.bin/egor_gp.bin files when the env variable EGOR_USE_GP_RECORDER is set.
The gpqa executable loads binary GP files and computes GP QA metrics: Q2 and PVA (see paper)