Revert "chore: replace Signature with PrimitiveSignature" #2143

Job	Run time
miri --no-default-features	4m 26s
test ubuntu-latest stable --no-default-features	1m 23s
miri	4m 25s
check no_std	41s
test ubuntu-latest stable	1m 22s
miri --all-features	4m 25s
test ubuntu-latest nightly --no-default-features	48s
clippy	46s
test ubuntu-latest nightly	50s
docs	32s
test ubuntu-latest 1.79 --no-default-features	40s
features stable	2m 16s
test ubuntu-latest 1.79	39s
fmt	12s
features stable --all-targets	3m 24s
wasm	41s
test windows-latest stable --no-default-features	3m 21s
features nightly	1m 39s
test windows-latest stable	2m 59s
features nightly --all-targets	2m 44s
test windows-latest nightly --no-default-features	1m 51s
test windows-latest nightly	2m 23s
test windows-latest 1.79 --no-default-features	1m 44s
test windows-latest 1.79	1m 21s
test ubuntu-latest 1.79 --features json	38s
test windows-latest 1.79 --features json	1m 50s
test ubuntu-latest nightly --all-features	1m 12s
test windows-latest nightly --all-features	3m 22s
ci success	2s
	52m 36s

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