Add panels for network compression

[amnonh]

Scylla Enterprise has metrics for network compression, we should show that

[amnonh]

@michoecho I'm not expecting you to add anything, I need an example of those metrics

[michoecho]

@michoecho I'm not expecting you to add anything, I need an example of those metrics

You can use https://argus.scylladb.com/test/560830b0-a699-4028-8278-7d88d50a2693/runs?additionalRuns[]=5f1c8ee7-7df1-4969-b2aa-eecee660312f as an example workload run with compression metrics scraped.

Compression metric names start with scylla_rpc_compression_.

[tzach]

@zseta FYI

[mykaul]

The panels should show compression ratio (per my discussion with @amnonh )

[amnonh]

Fixed by #2369