Files view performance

[schellj]

The files view contains folders with links that expand the given folder, but also all of the other folders that are already expanded. It takes a long time to load when there are a lot of expanded folders. This can be particularly problematic when there are realms that have a lot of folders/subfolders and eventually bots issue repeated requests to the files view with a large number of expanded folders, which can cause server load issues. Consider making it so that only one or a limited number of folder branches are expanded at once, or some other way to prevent performance issues.