In order to allow the bootloader to do preliminary CPUID validation
while UEFI is still handling displaying information to the user, split
most of the kernel's CPUID handling into a library to be used by both
kernel and boot.
Implement the syscalls necessary for threads to create other threads in
their same process. This involved rearranging a number of syscalls, as
well as implementing object_wait and a basic implementation of a
process' list of handles.
Introduces the cpu_features.inc table to enumerate the CPU features that
j6 cares about. Features in this table marked CPU_FEATURE_REQ are
considered required, and the boot process will log an error and halt
when any of these features are not supported. This should save me from
banging my head against the wall like I did last night with the missing
pdpe1gb feature.
