[native/rust_library] Adding openssl, base64, anyhow dependencies

Summary:
This diff introduces adding the following Rust dependencies:

• OpenSSL: We need the OpenSSL crate for the signing capabilities in D5999. We are using vendored OpenSSL, in this case, the system OpenSSL library will be used (linked).
• Base64: We are passing and getting the signed string from and to the Tunnelbroker in the Base64 format. The dependency is used in D5999.
• Anyhow: We are using this crate to pass errors to the function caller easily. First, this crate is used in D5999.

Linear task: ENG-1333

Test Plan: All CI gates are passed.

Reviewers: jon, varun, ashoat

Reviewed By: jon, varun, ashoat

Subscribers: ashoat, tomek, atul

Differential Revision: https://phab.comm.dev/D5998