Disable default features for `aws-lc-rs` #1465

Job	Run time
Build rustls-cert-gen as a standalone package	31s
Validate external types appearing in public API	1m 19s
build (macOS-latest, stable)	2m 50s
build-windows	10m 43s
build (ubuntu-latest, stable)	3m 6s
Measure coverage	5m 59s
build (ubuntu-latest, beta)	3m 6s
Format & clippy	5m 8s
build (ubuntu-latest, nightly)	3m 7s
Documentation (stable)	53s
build (ubuntu-latest, stable 7 months ago)	3m 7s
Check semver compatibility	3m 23s
Documentation (nightly)	52s
	44m 4s

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