Changes the default grpc client/server histogram buckets from the
defaults to better track the long tail of slow requests. Removes `.005`
and `.25` granularity in favor of adding the larger values of `45` and `90`
to avoid changing the cardinality.
```
# Before, the default prometheus buckets
[]float64{.005, .01, .025, .05, .1, .25, .5, 1, 2.5, 5, 10}
# After
[]float64{.01, .025, .05, .1, .5, 1, 2.5, 5, 10, 45, 90}
```
Fixes https://github.com/letsencrypt/boulder/issues/6384
07d6713736