ci: Use reusable workflows for fmt and security_audit #494

Job	Run time
clippy	13s
msrv (ubuntu-latest)	42s
test (ubuntu-latest, nightly)	14s
msrv (windows-latest)	1m 23s
test (ubuntu-latest, beta)	13s
test (ubuntu-latest, stable)	18s
test (windows-latest, nightly)	34s
test (windows-latest, beta)	31s
test (windows-latest, stable)	1m 28s
test (macos-latest, nightly)	14s
test (macos-latest, beta)	15s
test (macos-latest, stable)	11s
fmt / fmt	12s
security_audit / security_audit	2m 47s
	9m 15s

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