[Documentation]: Add suggestions for when .ef files are recommended to add for catalog

[wyz2368]

Requested documentation improvement

1. In the latest guidance for adding games to catelog, adding .ef file is said to be optional. It would be great to add something like Rahul's comment "generally we are not adding .ef files unless they significantly differ from what we can create with draw_tree". This would clarify when .ef files are preferred.
2. Adding naming guidelines might also be good for the guidance.
3. When I built the html to check the games added to catelog locally, I realized that I needed to build all docs and needed to add some dependence such as an installation of opsnspiel. We could make this simpler for merely testing if games have been successfully added to the catelog.