Replace lazy_static with std::sync::OnceLock in nats-server #4486

Job	Run time
check feature flags (ubuntu-latest / stable)	15m 53s
check examples (ubuntu-latest / stable)	56s
check format (ubuntu-latest / nightly)	12s
check docs (ubuntu-latest / stable)	1m 3s
check licenses (ubuntu-latest / stable)	27s
check linter (ubuntu-latest / stable)	1m 26s
check minimal versions of transitive dependencies (ubuntu-latest / stable)	1m 31s
check minimal supported rust version (ubuntu-latest / msrv)	45s
check spelling (ubuntu-latest / nightly)	6m 3s
test (ubuntu-latest / stable)	8m 25s
test (macos-latest / stable)	9m 40s
test (windows-latest / stable)	6m 48s
	53m 9s

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