common/timedmutex: clean and improve

[shazbert]

PR Description

• Reduce go routine spawn and inline waitgroup action when calling LockForDuration
• reuse timer instead of allocating on ever potential rest call
• rm rw mutex if nonce not required it shouldn't lock anyway so might be able to read field exposed without protection, if not it will be a rolling gate with the main mutex.
• Add benchmark comment from master to this.

Fixes # (issue)

Type of change

Please delete options that are not relevant and add an x in [] as item is complete.

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

How has this been tested

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration and also consider improving test coverage whilst working on a certain feature or package.

• [ ] go test ./... -race
• [ ] golangci-lint run
• [ ] Test X

Checklist

• [ ] My code follows the style guidelines of this project
• [ ] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation and regenerated documentation via the documentation tool
• [ ] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally and on Github Actions with my changes
• [ ] Any dependent changes have been merged and published in downstream modules