dynamic_bitset move CTOR and operator should be noexcept if C++ standard is 17 or higher

[d3matt]

The underlying std::vector's move CTOR and operator became noexcept with C++ 17. boost::dynamic_bitset should be able to follow suit in that case

[d3matt]

I'm pretty sure the noexcept specifier should match the one from std::vector. Something like:

noexcept(std::allocator_traits<Allocator>::propagate_on_container_move_assignment::value
|| std::allocator_traits<Allocator>::is_always_equal::value)