A simple export of config and config_plugins will show you a list with all the moodle and plugins settings and its value.
I used this solution in some projects to keep a record of the settings.
What you get is only the setting name, not a description. Then you must cross the tables information with the moodle language strings to get the description. That could be more complex and will require some coding. A local plugin for it would be great.
The changes tracking can be do it exporting config_log table as Stuart mentioned. With the right query you can get the list sorted by plugin and date.