spdm_crypt_lib: Expose the base_hash_algo

[alistair23]

The base_hash_algo is useful to know if you are using libspdm as a
library.

Reading it from the libspdm_context_t struct isn't ideal as the struct
is private and also doesn't work if using Rust for the implementation.

This commit exposes the base_hash_algo publicly using a helper
function.

This PR also fixes the documentation in include/library/spdm_crypt_lib.h.

[steven-bellock]

also doesn't work if using Rust for the implementation.

Are you saying that it's difficult / impossible for Rust to get the BaseHashAlgo via libspdm_get_data?

[alistair23]

Honestly, I forgot about libspdm_get_data()...

That does work. libspdm_get_data() is a little clunky as you end up with something like this

    let mut spdm_algo_base_hash = SpdmAlgoBaseHash(0);
    let hash_dptr = &mut spdm_algo_base_hash.0 as *mut _ as *mut c_void;

    let ret = libspdm_rs::libspdm_get_data(
        cntx_ptr,
        libspdm_rs::libspdm_data_type_t_LIBSPDM_DATA_BASE_HASH_ALGO,
        &parameter as *const libspdm_rs::libspdm_data_parameter_t,
        hash_dptr,
        &mut data_size,
    );

    if LibspdmReturnStatus::libspdm_status_is_error(ret) {
        return Err(ret);
    }

but it works. I can close this if that's the preferred approach

[jyao1]

if you want to expose, then we need to expose all algorithms, including hash, asym, req_asym, dhe, aead, etc.

[alistair23]

No worries. I'm going to close this then