Implement Rust evmc-host crate to consume VMs

[axic]

No description provided.

[axic]

An implementation exists here: https://github.com/second-state/rust-ssvm

[CaptainVincent]

An implementation exists here: https://github.com/second-state/rust-ssvm

Below things are being processed and we will update this issue as we make progress.

1. We will try to keep EVMC separate from rust-ssvm make them more independent at first.
2. Upgrade our codebase EVMC version from 6.x to 7.x.

[CaptainVincent]

Stage 1 is completed. We separate evmc-client with evmc ABI version 6 from rust-ssvm.

fork official repository with tag v6.3.1-rust-evmc-client

Now we will migration evmc-client to ABI version 7 and upstream it.

[axic]

Sounds good, thanks!

[CaptainVincent]

We already migrate our evmc-client to support evmc v7.3.0 in new branch.
https://github.com/second-state/evmc/tree/rust-binding-client

Temporary use Hera as the ewasm engine who support evmc v7.3.0 for testing the newer evmc-client mentioned before. (Run example/test pass)
https://github.com/second-state/rust-ssvm/tree/upgrade-evmc-client

I will add some unit test cases and update license meet official requirement in next stage before PR it.