feat: remove old `VersionedHashmap` data struct #1650

Job	Run time
cargo-lint / cargo-doc / doc	34s
cargo-lint / cargo-semver / Check semver	36s
cargo-lint / cargo-dry-publish / publish	17s
cargo-lint / cargo-nursery-base / cargo-udeps / Check udeps	47s
cargo-lint / cargo-nursery-base / cargo-lint / lint	1m 41s
cargo-lint / cargo-nursery-base / cargo-audit / Audit	6m 37s
cleanup	0s
cargo-publish	0s
	10m 32s

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