Add duneuro examples to gallery

content/gallery/duneuro.md

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+title = "Electroencephalography Forward Problem"
+content = "carousel"
+image = ["/img/duneuro_01.png", "/img/duneuro_02.png", "/img/duneuro_03.png"]
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+A CutFEM discretization of the EEG forward problem ([Nüßing 2018](https://nbn-resolving.org/urn:nbn:de:hbz:6-67139436770)).
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+The geometry is obtained from an MRI scan of a healthy subject, the image is segmented and a level-set description is generated.
+To avoid problems with creating a geometry-conforming mesh, a CutFEM method is employed which directly uses the level-set information.
+Using the forward solution given by Dune, the origin of a measured potential distribution at the head surface is estimated.
+Visualized using Paraview and Blender.