Turn off wasm_reference_types in Wasmi

[jayz22]

What

Disable wasmi reference_typesand make all wasmi feature selections explicit.
Also did a pass-by clean up on the fuel configs code.

Why

bulk_memory and reference_types are both post-MVP features.
We use 1 extensively for object init/copy between host and guest.
We do not use 2 at all. We are not using ExternRef and we are limiting table count to 1 (via resource limiter).

Known limitations

[TODO or N/A]

[graydon]

Generally ok but needs a protocol gate (at least on the part that's a change -- I take it the bulk-memory one is not a functional change, just setting explicitly what is already being set implicitly?)