Investigate Wasm module linking through tables for providing a cross platform ABI

[nicholasjackson]

Rather than write an ABI for every language that will be compiled to Wasm it might be possible to create a single module that provides importable functions to other libraries using the linking mechanisms of Wasm Tables. Functions such as memory allocation, a string to pointer conversion, etc could be provided as a linked library rather than an importable module. This would vastly save duplication as only the definitions for the external functions would need to be created as language-specific imports. The implementation would be an externally linked library.

The initial intention of this would be to provide core Wasp functionality but this capability could be extended for plugin developers.