Add new cpuid label "feature.node.kubernetes.io/cpu-cpuid.AVX10_VERSION"
that advertises the supported version of AVX10 vector ISA.
Correspondingly, the patch adds AVX10_VERSION to the "cpu.cpuid" feature
for NodeFeatureRules to consume.
This makes cpu.cpuid on amd64 architecture a "multi-type" feature in
that it contains "flags" and potentially also "attributes" (the only
cpuid attribute so far is the AVX10_VERSION).
Convert the cpu source to do feature discovery and creation of feature
labels separately.
Move cpuidutils from source/internal to the source/cpu package. Change
the cpuid custom rule to utilize GetFeatures of the cpu source.
Also, add minimalist unit test.
Remove 'cpuid', 'pstate' and 'rdt' feature sources and move their
functionality under the 'cpu' source. The goal is to have a more
systematic organization of feature sources and labels. After this change
we now basically have one source per type of hw, one for kernel and one
for userspace sw.
Related feature labels are changed, correspondingly, new labels being:
feature.node.k8s.io/cpu-cpuid.<cpuid flag>
feature.node.k8s.io/cpu-pstate.turbo
feature.node.k8s.io/cpu-rdt.<rdt feature>
