WIP: CacheKVStore dirty items sorted

[mossid]

• Targeted PR against correct branch (see CONTRIBUTING.md)

• Linked to github-issue with discussion and accepted design OR link to spec that describes this work.

• Wrote tests

• Updated relevant documentation (docs/)

• Added entries in PENDING.md with issue #

• rereviewed Files changed in the github PR explorer

Closes: #2286

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For Admin Use:

• Added appropriate labels to PR (ex. wip, ready-for-review, docs)
• Reviewers Assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[alexanderbez]

bump @mossid -- any updates you can share on this?

[alexanderbez]

bump @mossid

[cwgoes]

This is a good idea regardless, but if it's a significant amount of work I don't think it's super high-priority - we might be better served by writing more extensive gaiad benchmarks first. Up to you @mossid.