refactor: Take `impl BlockStore` instead of `&impl BlockStore` in general #73

Job	Run time
run-headless-tests (ubuntu-latest, firefox)	27s
run-cargo-tests (stable)	1m 17s
run-checks (stable)	2m 28s
run-headless-tests (ubuntu-latest, chrome)	15s
run-cargo-tests (nightly)	1m 52s
run-checks (nightly)	1m 47s
run-checks (1.75)	57s
	9m 3s

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