Simplify SDK with go:wasmexport

[hariso]

Feature description

The Processor SDK is currently communicating with Conduit through a "command-and-response" loop, where the Processor SDK runs a loop in which it asks Conduit for a new command to execute. The commands are actually processor methods, e.g. Open, Process, etc. The reason for this is that WASM modules that are written in Go cannot export functions.

However, the go:wasmexport directive is going to be added to Go 1.24. Using this directive and simply exporting all of the processor methods would simplify our code.