Add RIPEMD160 support

Currently OpenSSL.jl does not include support for RIPEMD160. After having been moved to legacy in OpenSSL 3.0, later versions of OpenSSL 3 and OpenSSL 4 all suppport the digest type. This can be easily added to OpenSSL.jl as follows:

using OpenSSL

EvpRIPEMD160()::OpenSSL.EvpDigest = OpenSSL.EvpDigest(ccall((:EVP_ripemd160, OpenSSL.libcrypto), Ptr{Cvoid}, ()))

ctx = EvpDigestContext()
digest_init(ctx, EvpRIPEMD160())
digest_update(ctx, UInt8.(codeunits("hello")))
@show hash1 = digest_final(ctx) # 20-byte Vector{UInt8}

@show hash2 = digest(EvpRIPEMD160(), IOBuffer("hello"))

@show hash1 == hash2

Would a patch for this be useful here? If we let things fail in OpenSSL early versions it is a one-liner patch to add EvpRIPEMD160(), otherwise it may need several lines to add both EvpRIPEMD160() and load_legacy_provider() for early 3.0 OpenSSL.

Start by reading the existing digest constructors and the EvpDigest, digest_init, digest_update, digest_final, and digest entry points in OpenSSL.jl. Try the RIPEMD160 example from the issue against the supported OpenSSL versions; done means EvpRIPEMD160 is available and both shown hashing paths produce the same 20-byte digest.

Written by the indexing model from the issue text.