feat: metrics for each MV/Sink's latency

[fuyufjh]

Is your feature request related to a problem? Please describe.

Now we only have a global barrier latency.

Describe the solution you'd like

No response

Describe alternatives you've considered

No response

Additional context

No response

[lmatz]

Right now the barrier latency is calculated at https://github.com/risingwavelabs/risingwave/blob/main/src/meta/src/barrier/creating_job/barrier_control.rs#L288
when all the barriers are collected from worker nodes

We can calculate the latency for each MV/Sink at each CN instead of at meta node. We then take the maximum of them on Grafana dashboard via PromQL.
Since the barrier interval is large enough, e.g. 1s by default, even if there is some clock drift among different CNs, it should be ok.

cc: @lin0303-siyuan