Create RequestInterceptor

[MulverineX]

Accessed through MercuryContext.requests

• Add efficient shims to fetch & websocket modules
• Add receiveOutgoing & receiveIncoming methods; non-blocking event listeners to receive request data based on either a domain match or URL regex, does not tamper with request contents.
• Add modifyOutgoing & modifyIncoming methods; blocking callbacks that allow for request modification or cancellation based on either a domain match or URL regex.
• Add replace method; blocking callbacks that allow for manual handling of the request response based on either a domain match or URL regex (eg. Database endpoint -> native FFI call)
• Add cleanup method; takes interceptor UIDs returned from established methods & removes them from the instance.

The idea here is to provide a better API than the current HTTPClientInterceptor system