docs: add docs for `starknet-curve` #602

Job	Run time
Build C++ integration example	1m 21s
Build starknet-curve features	22s
Build starknet-crypto features	38s
Build starknet-core features	1m 9s
Build starknet-providers features	1m 15s
Build starknet-signers features	55s
Build starknet-accounts features	1m 26s
Build starknet-contract features	1m 3s
Build starknet-macros features	40s
Build starknet features	1m 53s
	10m 42s

Provide feedback