Implement SharedResourcePool

[YangchenYe323]

What changes are proposed in this pull request?

Implemented SharedResourcePool, which unlike DynamicResourcePool, shares resources across multiple acquire calls and never blocks.

Why are the changes needed?

We might want to replace the current ClientPool model to share clients within the same FileSystemContext, which might help with issues like https://github.com/Alluxio/alluxio/issues/15893

Also, sharing client makes sense as clients are pretty much stateless and already synchronized. There's very little benefit creating many instances of the client anyway, since the underlying connection channels are already shared.

Does this PR introduce any user facing changes?

No

[YangchenYe323]

@dbw9580 Would you mind taking a look at this? Appreciate your feedback.

[YangchenYe323]

@ssz1997 For your visibility here.

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in two weeks if no further activity occurs. Thank you for your contributions.

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed in two weeks if no further activity occurs. Thank you for your contributions.