New repo request "stdplus"

[William Kennington]

I'd like to request a new repo be created where we can put universally
used c++ functions and classes that any of our projects could inherit
from. This would not be allowed to have any runtime dependencies
outside of the typical built-in ones (libstdc++, libc, and the kernel
syscall interface).

Right now I've got a smart file descriptor and signal blocking
function which I'd like to include. It would look something like
(although I actually want to break this down into a uniquefd and
dupablefd for the purposes of stdplus):
https://github.com/openbmc/gpioplus/blob/1d97c45aa75957e9e8965e33f1f28985cf88d22d/src/gpioplus/internal/fd.hpp

Let me know what you think,
William