Allow selecting ReCaptcha's "RequestMethod" rather than using the default POST method

Google's ReCaptcha uses "POST" as the default "RequestMethod". However, it fails on certain (mostly shared hosting) servers due to incompatible configuration of file_get_contents().

Workaround is a manual code change in order to set the default as CurlPost or another from the available choices. There has to be an easier option to choose this without having to edit code. May be, during ReCaptcha set up, our system should try different methods and remember the "RequestMethod" that works.

Or, based on statistical info, we should have the default set to something else.