Introduce noheader and nofooter CBI-Dispatcher config

libs/web/luasrc/dispatcher.lua

@@ -672,15 +672,19 @@ local function _cbi(self, ...)
 
 	local pageaction = true
 	http.header("X-CBI-State", state or 0)
+	if not config.noheader then
 		tpl.render("cbi/header", {state = state})
+	end
 	for i, res in ipairs(maps) do
 		res:render()
 		if res.pageaction == false then
 			pageaction = false
 		end
 	end
+	if not config.nofooter then
 		tpl.render("cbi/footer", {pageaction=pageaction, state = state, autoapply = config.autoapply})
 	end
+end
 
 --- Create a CBI model dispatching target.
 -- @param	model	CBI model to be rendered