buildroot: remove obsolete sudo-install-sudoers-so.patch

The issue the patch addresses is not present in current buildroot version

Fixes #1
fix nfs issues

- nfsv4 support was broken due to missing dependencies
- nfsd.ko was missing from image

Fixes #2
bin/bundle: rework image size calculation

Instead of relying on a pre-determined image size,
image size is calculated as the size of the rootfs
tarball plus extra size.

Reflecting the change in semantics, earlier -s/--size option is
replaced with -x/--xsize.

Fixes #3
fix urls for kernel and grub
buildroot: add htop