provide an option to use openssl to support FIPS 140 for blob storage

[Leavrth]

I found that the SDK calls generation_authorization to generate the signature when use shared key to access blob storage.

azure-sdk-for-rust/sdk/storage/src/authorization/authorization_policy.rs

Line 46 in 0d09ed3

let auth = generate_authorization(

However, it directly uses the sha2 library to generate hmac hash.

azure-sdk-for-rust/sdk/storage/src/authorization/authorization_policy.rs

Line 98 in 0d09ed3

let auth = crate::hmac::sign(&str_to_sign, key).context(

But to support FIPS 140, please provide an option to use openssl to generate hmac hash.