Update README.md to match the fact that this is a kernel repository
Update README.md to match the fact that this is a kernel repository

Everything prior to this commit has been filter-branched away from
an old monolithic KnightOS repository, containing both the kernel
and the userland code.  Accordingly, there will be a couple of fixup
commits to get everything straightened out.

KnightOS/kernel,calcdude84se/knightos-kernel,unlimitedbacon/kernel,KnightOS/kernel