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

[lordspacehog]

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:
chipsalliance/rocket-chip#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.

[sequencer]

I do like this idea, and my suggestion is you can sending small APIs and PR to this folder, this is not released by we can release it in the future(in another release target), while don't need to be as stable as chisel does.