OCI-compatible proposal for wrappering wasmtime

[leonwanghui]

Hi firstly of all I really like this idea, and I have been confirmed that container wrapper+wasm/wasi runtime could bring some much of new opportunity no long after, despite wasm/wasi is not mature for now.

After some digging around with some other projects (such like kata), I think it could be better if we could wrapper wasmtime with OCI runtime specification, which leads to some benefits below:

• Make wasmtime as a gRPC service rather than an executable file
• Make this shim layer more general because of OCI (reduce some code deduplication with other container runtimes, ie. easy to develop)
• Make oci-wasmtime wrapper written in Rust so as to easily call wasmtime runtime API library

Lastly again I believe in heart that this is a great vision to redefine the future of new generation computation runtime.