PQ compression: metrics

[yaauie]

Expose encode/decode metrics for PQ compression in pipeline.${pipeline_id}.queue.compression namespace as specified in #17819

name	definition	expected value range
encode.spend.lifetime	(encode_time / uptime)	[0,(N_CPUS)]
encode.ratio.lifetime	(compressed_bytes / decompresssed_bytes)	[0,1]
decode.spend.lifetime	(decode_time / uptime)	[0,(N_CPUS)]
decode.ratio.lifetime	(decompressed_bytes / compresssed_bytes)	[1,)

[robbavey]

@yaauie Can this be closed now?

[robbavey]

Closed by Pq compression user metrics #18227