Revert "chore: replace Signature with PrimitiveSignature" #2145

Job	Run time
test ubuntu-latest stable --no-default-features	1m 26s
check no_std	46s
clippy	44s
test ubuntu-latest stable	1m 10s
test ubuntu-latest nightly --no-default-features	47s
docs	34s
test ubuntu-latest nightly	48s
features stable	2m 16s
test ubuntu-latest 1.79 --no-default-features	44s
features stable --all-targets	3m 31s
fmt	11s
features nightly	1m 33s
test ubuntu-latest 1.79	38s
features nightly --all-targets	3m 10s
test windows-latest stable --no-default-features	3m 22s
miri --no-default-features	4m 46s
test windows-latest stable	2m 31s
wasm	42s
miri	4m 43s
test windows-latest nightly --no-default-features	2m 0s
miri --all-features	7m 18s
test windows-latest nightly	2m 47s
test windows-latest 1.79 --no-default-features	1m 33s
test windows-latest 1.79	1m 31s
test ubuntu-latest 1.79 --features json	44s
test windows-latest 1.79 --features json	1m 21s
test ubuntu-latest nightly --all-features	1m 11s
test windows-latest nightly --all-features	2m 22s
ci success	4s
	55m 13s

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