Implement GOMAXPROCS injection as a composable PreCreate runtime handler
hook instead of inline logic in container_create.go. This follows the
existing CRI-O hook architecture (like HighPerformanceHooks) and allows
the GOMAXPROCS hook to compose with other hooks via CompositeHooks.

Key changes:
- GomaxprocsHooks: PreCreate hook that reads CPU shares from the OCI
  spec, calculates GOMAXPROCS with a configurable floor, and injects
  the env var for burstable/best-effort pods
- CompositeHooks: chains multiple RuntimeHandlerHooks implementations,
  enabling GOMAXPROCS to work alongside high-performance hooks
- HooksRetriever.Get(): builds a hook chain when inject_gomaxprocs > 0
- Config field, CLI flag, annotation, docs, completions, and tests

The hook fires for all OCI runtimes and skips guaranteed pods,
workload-partitioned pods, pods with CPU limits (Go 1.25+ auto-detects),
and pods that already have GOMAXPROCS set.

Signed-off-by: Peter Hunt <pehunt@redhat.com>
Co-authored-by: Harshal Patil <12152047+harche@users.noreply.github.com>