Use @Project on controllers, don't call method

Created by: cirosantilli

Also memoize the method through the unless @project line to ensure that other methods in ApplicationController that rely on it can call it efficiently.

This PR makes things much more efficient: before it def project was already called as a filter before every project controller, setting @project, but many places in the controllers re-called project, which was not memoized, instead of using the instance.