Using ckms bench as an regression testing tools

[serene-kitfisto-8899]

The new kms cli aka ckms as a bench option :

$  cargo r --bin ckms bench -v -b 1000 -n 1000
...
Encryption time XXX XX XXµs => XX 301µs/batch => XXµs/value
Decryption time XXX XX XXµs => XX 648µs/batch => XXµs/value
Amortized encryption time (1 threads): XX XX XXµs => XXX XXXµs/batch => XXXµs/value
Amortized decryption time (1 threads): XX XX XXµs => XXX XXXµs/batch => XXXµs/value

It's a perfect tool for regression testing : it is a process that ensures that software still performs as expected, even after a change.

For that we need a stable and dedicated platform for benchmarking. The hardware must stay the same between versions of the KMS.