Auto-light-compensation or magic wands for a video is in the wishlist for every video editor, unfortunately, each video may contain major changes in illumination in the same scene, which makes a plugin like this a must but also a complicated thing to achieve.
Several tools on the kdenlive software allow you to run both "Color" and "Color correction" for your videos. The list includes but not limits to:
Colour Correction Plugins
For your case, the "Curves" Plugin may do an awesome work if you apply the effect directly on the video track, after wich you simply adjust the levels that will be applied to all the video elements on that track. This way in a few clicks you can adjust the properties of every video on that track. Nevertheless it will constantly apply the same effect in all the scenes, which may not be what you wish for an auto-light-compensation.