Reuse memory in assign

[kelbon]

• adds reusing memory in assigments and emplace
• adds 'replace_with_bytes' (effectively reserve) 'replace_with' (assing with strong exception guarantee)
• removes strong exception guarantee from assignments (now basic guarantee), because its too much to not reuse memory, problem very similar to std::variant::valueless_by_exception

Maybe:

• copy_with deprecated (not depends on Alloc and SooS), because of that materialization and copy assign/copy ctor cannot detect if they require allocation staticaly, so aa::unreachable_alloc less usable