Deduplicate Rust attestation protos definition

[ipetr0v]

We currently have conflicting Rust definitions for our DICE protos.
We have the oak_remote_attestation crate building the protos.
And the oak_attestation_verification building them as well.

And since the Orchestrator has to use both crates, it gets conflicting definitions. I.e. we cannot pass the evidence to the verify function, because it was built in a different crate.

[ipetr0v]

As a temporary solution we are going to serialize and deserializa protos in-place into structs from a different crate