ref. https://github.com/jrl-umi3218/jrl-cmakemodules/issues/338
and fix deprecation warning about CMake 3.5 from CMake 3.27

* optional: expose to-value converter for boost::none_t (and std::nullopt_t if possible)

+ add src/optional.cpp to expose none types
+ this allows to have None as a default arg value for functions (also, shows up in stubs)
+ also allows to have none_t return/argument type

* Run pre-commit

+ default is boost::optional<T>
+ add test for boost::optional

* add test_std_vector.py
* fix copyable.hpp's include guards & namespace
* same for pickle-vector
* expose std::vector for VectorXd, MatrixXd, VectorXi, MatrixXi

* cmake: use REQUIRED

* core: fix issue with Python 3.10 and more

* core: fix logic

* core: fix

* core: further fix

* Core: use official solution

Co-authored-by: Guilhem Saurel <guilhem.saurel@laas.fr>

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci



* core: fix

Co-authored-by: Guilhem Saurel <guilhem.saurel@laas.fr>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

fix build on NetBSD 9.2