Keep track of all presets, plug-ins, extensions, mogrts?

In short, no, there's no easy way as each of those things you listed are all installed to separate places. Many people manually manage their library in folders then copy items over to each new version. 

If plug-ins are installed to the Media Core folder (many are) as opposed to the Premiere version folder, then those will show up between versions (assuming the plug-in developers have enabled support for each new version).

If you use tools from aescripts.com (they have plenty of Premiere tools, but as the name suggests, it is an AE-centric site), they do have a manager app that's essential for making script, plug-in, and extension installation and management much, much easier than doing it manaully.