Add context

This commit adds and passes context around to (almost) every function.
This allows cancelling (almost) every function call globally.

internal/dis/component/server.go

@@ -15,5 +15,5 @@ type Servable interface {
 	Routes() []string
 
 	// Handler returns the handler for the requested route
-	Handler(route string, context context.Context, io stream.IOStream) (http.Handler, error)
+	Handler(ctx context.Context, route string, io stream.IOStream) (http.Handler, error)
 }