Upstream TDCALL library as crate to crates.io

[vijaydhanraj]

We are enabling TD partitioning support in SVSM (https://github.com/coconut-svsm/svsm). Our current implementation uses tdx-tdcall library from the TD-shim project. But rather than do copy-paste-modify, request is to upstream TDCALL library to crates.io so that TD partitioning code can directly refer to it from crates.io.

• What interface is needed – the APIs to upload to Crates.io
  • We use most of TDCALL functions as part of tdx-tdcall folder, so the request is to upstream all the pub interfaces that are part of it.

[jyao1]

See the first version at https://crates.io/crates/tdx-tdcall