I am happy it worked out! 
These ppas are for development, so the release is not stable.
IPU stays for Image Processing Unit (6 for 6th generation) and it is an Intel Input System + Processing System.
Try to reinstall cheese or camera, but I am glad the issue is solved (more or less).
Also @toorandom, since you have now deleted all the wrong packages and repositories, make sure you have the three you needed at the very beginning. Namely,
sudo apt install oem-somerville-treecko-meta
sudo apt install intel-ipu6-dkms
sudo apt install libcamhal-ipu6epmtl