Finalize flyteidl Rust crate

[austin362667]

Tracking issue

flyteorg/flytekit#2328

Why are the changes needed?

Expose Flyteidl Rust crate based on #5187

It can be added as a local dependency by Flyekit.

What changes were proposed in this pull request?

Initialize cargo.toml and lib.rs.

How was this patch tested?

Setup process

cargo b --release

Screenshots

Check all the applicable boxes

• I updated the documentation accordingly.
• All new and existing tests passed.
• All commits are signed-off.

Related PRs

Docs link

[kumare3]

Will we build a rust client crate here?

[austin362667]

I don't think so for now.
We just need to expose flyteidl as a Rust Crate in advance. So it can be added as dependency for underlying Rust client.

[austin362667]

For example, to add a local dependency, you can do the following:

https://github.com/flyteorg/flytekit/blob/b132c892ee09c1e91d8eeeae8e3d8dd2857a990a/flyrs/Cargo.toml#L20

Or add a dependency via git, you can:
https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#specifying-dependencies-from-git-repositories