ci: add sconification workflows #55

Job	Run time
build-and-test / build_and_publish	5m 19s
Determine image tag	3s
Build OCI images (pre-compute) / build	6m 7s
Build OCI images (post-compute) / build	7m 30s
Build TEE images (registry.scontain.com/scone-debug/iexec-sconify-image-unlocked, 5.9.1, /app/tee...	1m 12s
Build TEE images (registry.scontain.com/scone-debug/iexec-sconify-image-unlocked, 5.9.1, /app/tee...	1m 22s
	21m 33s

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