[Feature Request] Optionally movable atomic_t

[elad335]

This is not the first time I've came across this problem, only recently in #12921 I've worked-around this limitation with shared ptr which is not ideal. I understand that this is a limitation derived from std::atomic but it doesn't make sense to enforce it sometimes.

[Nekotekina]

I don't understand the problem, you can just put atomic_t directly in std::map container