This should remove nearly all usage of `sp-std` except:
- bridge and bridge-hubs
- a few of frames re-export `sp-std`, keep them for now
- there is a usage of `sp_std::Writer`, I don't have an idea how to move
it

Please review proc-macro carefully. I'm not sure I'm doing it the right
way.

Note: need `/bot fmt`

---------

Co-authored-by: Bastian Köcher <git@kchr.de>
Co-authored-by: command-bot <>