metrics: Increase the resolution of histogram metrics (#7335)

* metrics: Increase the resolution of histogram metrics

These metrics are using the default histogram buckets:
```
pub const DEFAULT_BUCKETS: &[f64; 11] = &[
    0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 10.0,
];

```

Which give us a resolution of 5ms, that's good, but there are some subsystems
where we process hundreds or even a few thousands of messages per second like
approval-voting or approval-distribution, so it makes sense to increse the
resoution of the bucket to better understand if the procesisng is in the range
of useconds.

The new bucket ranges will be:
```
[0.0001, 0.0004, 0.0016, 0.0064, 0.0256, 0.1024, 0.4096, 1.6384, 6.5536]
```

Signed-off-by: Alexandru Gheorghe <[email protected]>

* Use buckets with higher resolution

Signed-off-by: Alexandru Gheorghe <[email protected]>

---------

Signed-off-by: Alexandru Gheorghe <[email protected]>