Add seccomp into feature flags of youki to be compiled in #2101

Job	Run time
youki-build (x86_64, gnu)	1m 46s
youki-build (x86_64, musl)	2m 12s
youki-build (aarch64, gnu)	2m 3s
youki-build (aarch64, musl)	2m 12s
k8s-tests (x86_64, gnu)	1m 31s
containerd-integration-tests (x86_64, gnu)	5m 12s
oci-validation-go (x86_64, gnu)	1m 43s
oci-validation-rust (x86_64, gnu)	2m 48s
k8s-tests (x86_64, musl)	1m 34s
containerd-integration-tests (x86_64, musl)	5m 16s
oci-validation-go (x86_64, musl)	1m 52s
oci-validation-rust (x86_64, musl)	2m 43s
docker-in-docker (ubuntu-22.04)	12s
rootless-podman-test (x86_64, gnu)	1m 5s
docker-in-docker (ubuntu-20.04)	19s
rootless-podman-test (x86_64, musl)	47s
	33m 15s

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