Migrate away from deprecated functions in C++23

[Chocobo1]

https://stackoverflow.com/questions/71828288/why-is-stdaligned-storage-to-be-deprecated-in-c23-and-what-to-use-instead

[Chocobo1]

@arvidn
Please merge it into RC_2_0 and master. They are affected too.
Also can we expect a new maintenance release for RC_1_2? There are some nice small fixes accumulated.

[arvidn]

thanks! use of aligned_union and aligned_storage was removed in master a while ago. This still applies to RC_1_2 and RC_2_0 though

[Chocobo1]

use of aligned_union and aligned_storage was removed in master a while ago.

But I see you still have aligned_storage in master: https://github.com/arvidn/libtorrent/blob/master/include/libtorrent/aux_/aligned_storage.hpp