[Feature Request/Proposal] Upstream Utils from rocket-chip into chisel where applicable.

**Type of issue**: Feature Request

**Is your feature request related to a problem? Please describe.**
This is less of a feature request and more of a proposal/gauge of interest before i proceed with submitting PRs.
We're starting the process of splitting out the utils module in rocket-chip to be a more standalone library to make it easier for people to re-use those utils without needing to pull in the entire rocket tree. As part of this work we'd like to upstream whatever makes the most sense to upstream.

**Describe the solution you'd like**
It would be great if we can collaborate on selecting what should be pulled into chisel and what should be left as it's own library.

I think at a minimum we'd like to incorporate as many of the extension methods in the main package as possible. (https://github.com/chipsalliance/rocket-chip/blob/dev/src/main/scala/util/package.scala)

@sequencer: i think you had thoughts on this as well, would love to capture your insight here as well.

**Additional context**
Rocket chip issue i'm currently working:
https://github.com/chipsalliance/rocket-chip/issues/3596

Rocket chip Utils:
https://github.com/chipsalliance/rocket-chip/tree/dev/src/main/scala/util

**What is the use case for implementing this feature?**
Consolidate useful extensions in rocketchip into chisel for more widespread use.