Track, Agree Upon, and Document Breaking Semantic Changes

[rylev]

Below is a list of the breaking semantic changes to the Spin runtime that will be coming in Spin 3.0. Before we release, we should ensure that we are all of with these changes, and then we should document them.

• HttpRequestDenied used to be returned from wasi:http/outgoing-handler#handle but are now returned from wasi:http/types/future-incoming-response#get
• [Factors] Change how incoming-request.authority is set. #2723
• Deprecate execution of "uncomponentizable" WAGI modules #2552
• Remove HTTP trigger base option developer#1371
• Update language guide(s) for 3.0 developer#1376