Add InteractionHandler to Rust API

[emesare]

This would allow us to handle interactions programmatically from rust, a use case can be found in the flow graph example:

binaryninja-api/rust/examples/flowgraph.rs

Lines 52 to 53 in 6a63c17

	// TODO: Register BNInteractionHandlerCallbacks with showGraphReport pointing at our function
	// TODO: Idea: register showGraphReport that dumps a dotgraph to stdin

C++ API class:

binaryninja-api/binaryninjaapi.h

Line 16454 in 8767400

class InteractionHandler