Allow to template URLAction value
In current latest version of tryton application is possible to expose some routes to the client using the route decorator. But it's hard to expose them to users using tryton menu as you need to know the server URL in advance and this is not easy to know in advance.
In order to solve this, I propose to make clients append the current connection server url, to the action_url if this url starts with '/'. This is similar to the usage of links in a webpage.