plugin system

[pspsdev]

At current state it's very hard to use it, because one single unimplemented api can break everything. Would it be feasible to somehow have a plugin system so that user himself can write code to return response to web api. Such as window.atob just run it with any language and return it via some http/ws api or something else. This would also be useful if user would want to change how specific web api works compared to official lightpanda implementation.