http.server: Implement DELETE, PATCH; handle unknown methods

http.server: Implement DELETE, PATCH; handle unknown methods

Handle DELETE and PATCH.  Be lenient and hand URL query parameters to
the user with a DELETE.  There is debate about whether DELETE should
handle query parameters.  Additionally, some implementations even reject
DELETE requests with a body.  So, leave all these additional
"protections" for a later implementation (e.g. in furnace).

Treat unknown methods like requests without parameters.