Setting parity for remote serial

[Yurij Grechishhev]

> IOW, IMO, if we add "set serial parity",
> we should also alias "set remotebaud" to "set serial baud", and whatever
> other commands would make sense (which should be really simple to do).

That would be great. But it's more comprehensive patch that I have done.
Can we add all "set remotefoo" commands and then alias them
to "set serial foo" at once?
Related discussion:
https://sourceware.org/ml/gdb-patches/2001-09/msg00358.html