v2.0.0: Http api proc (#4)

* Add custom Caddy handlers and update config

Include custom Caddy handlers for error-body status rewriting and minimum response duration.
Wire handlers into the Caddyfile and xcaddy build, and document httpapi behavior.
Adjust fmt for Git Bash path conversion.

* Change min_duration to upstream rate limiter and lock versions and use simplefs changed cache directory to /cache

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* corrected minduration

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* updated actions to run go test and validate

* temporarily increase duration to something very high for testing

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* use env vars

* use env vars

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* redirect if waiting too long

* redirect if waiting too long

* redirect if waiting too long

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