Positional factory function for class palikka.components.http_kit.Http-kit.

Create http-kit component. `handler` should be handler function, var
pointing to such function or map with property `fn`. If handler is function
the value of `fn` property will be called with single argument, the system,
to construct the handler function.

Factory function for class palikka.components.http_kit.Http-kit, taking a map of keywords to field values.