Is your feature request related to a problem? Please describe.
The module can't be used in across node/browser/react-native environments by default. Because the http module is only available in node you have to use the browser bundle which is awkward if you're including cloudevents within a npm package you're using across different environments. Similar issue reported here #534

Describe the solution you would like to see
Remove the request helpers or break them out into a separate package.

Additional context
It feels like the core library should focus on the cloudevent spec (creating & validating events) only and leave the implementation of sending events up to the developer. I do see the value in having something available out the box, but in our case we have existing implementations in place for http/websockets etc.

To work around this we have to conditional import the browser bundle which is a lot more awkward than just a simpler, universal package.