Allow HTTP fetcher to make POST calls

@swilmes Thanks for requesting this feature. I've just faced the same case when I need to request endpoint with POST method. Your approach looks good, I just reformat it a little bit (fork and MR is created).
Needs review and testing.

Set request method with more compact way.

Thanks for the patch and elegant solution! I tested it, and it works like a charm.

Thanks for your contributions.

Automatically closed - issue fixed for 2 weeks with no activity.

Often POST requests require a body in the request. Is it possible now or should I create a ticket for that request?