generate and integrate CAR bundle

[raulk]

This issue tracks work being carried out in the raulk/initial branch of this repo:

• Remove reliance on wasm-builder from all actors
• Remove reliance on runtime-wasm feature from all actors.
• Compile actors to Wasm under the bundle module.
• Create a bundling utility to pack Wasm bytecode into a CAR with an index data structure enumerating actor types => CodeCID.
• Integrate bundling utility into build.
• Remove all knowledge of static CodeCIDs from actors, and migrate to an actor::is_builtin_actor syscall that returns whether a given CodeCID corresponds to a builtin actor, and to which from an enumerated set.
  • implement actor::is_builtin_actor(Cid) -> int32 syscall ref-fvm#342
• Load bundle CAR in ref-fvm conformance tests.
• Pass index structure to the FVM via contructor so it can handle the above syscalls.
• Run conformance tests.
• Do the same in Lotus.
• Publish cargo releases of fvm, fvm_shared, and other modules so we can specify versions in the Cargo.toml file instead of local paths.
• Make a release of builtin-actors/bundle, so it can be integrated upstream.

[jennijuju]

next item is in lotus hand now

[raulk]

Bundle is now integrated into Lotus via the FFI layer, for practical reasons. Namely: the fil_builtin_actors_bundle crates exports the CAR as a byte slice for easy consumption by other Rust crates (i.e. filecoin-ffi).