pkcs5: simple `pbes2::Params` constructors #1043

Job	Run time
build (1.65.0, thumbv7em-none-eabi)	1m 44s
build (1.65.0, wasm32-unknown-unknown)	1m 47s
build (stable, thumbv7em-none-eabi)	15s
build (stable, wasm32-unknown-unknown)	16s
test (1.65.0)	1m 59s
test (stable)	27s
minimal-versions / minimal-versions	39s
	7m 7s

Provide feedback