Be Able to Implement a Fixed DirectoryContainer Height

This will require another issue of implementing some sort of scrolling mechanism, which relates to https://github.com/JosephTLyons/termifind/issues/2. The point of this would be to limit the height of DirectoryContainers so that rows that wrap around aren't forced down much further because of one long DirectoryContainer. The same sort of statistical measurements that are used on truncating file names (Constant, Level, Average, Outlier) could be used to limit the height of a DirectoryContainer.