Switch create node to pass form data via request body, removing the
need for special handling in the _build_url method. Consequently remove
the string placeholder in the endpoint format string.
Remove unnecessary parameters of name and type from inclusion in the
json form data item, confirming they are ignored and required to be set
in the main form data.
Tested against jenkins 2.19.4.
Change-Id: I5f8f870a2ee3539505e984abccb0c87c632c1b9a