Add per-tenant cache utilisation metrics and/or logs

[dannykopping]

Is your feature request related to a problem? Please describe.
We need per-tenant metrics to determine who is hitting cache the hardest, storing the largest objects, etc.

Describe the solution you'd like
Add metrics/logs, and include the following information:

Hit/miss
Length of key
Length of value
Cache type
Latency

Describe alternatives you've considered
N/A

Additional context
N/A