Add a way to copy both size and capacity for containers #30

template<typename LHST, typename RHST>
LHST
capacity_copy_construct(const RHST& rhs)
{
   // default implementation
    LHST a{ rhs };
    a.reserve(rhs.capacity());
    return a;
}

template<>
cetl::VariableLengthArray<std::size_t>
capacity_copy_construct<std::vector<std::size_t>, std::vector<std::size_t>>(const std::vector<std::size_t>& rhs)
{
    // do special stuff here to copy construct VLA with the rhs.capacity()
}