07edb2483d
This removes all references to .../sbin for the guest additions and also installs all binaries to .../bin instead (so no more .../sbin). The main motivation for doing this is commit 98cedb3 (which unfortunately had to be reverted in a9f2e10) and pull request #9063, where the latter is an initial effort to move mount.vboxsf to .../bin instead of .../sbin. The commit I made afterwards is finishing the removal of .../sbin entirely.