Add a teaser video

[sarah-segel]

We could add a teaser video showing some functionalities of DeepCave, either to the readme or documentation. There is such a recorded video in the GDrive already, however, it is not up to date with the latest developments (https://drive.google.com/drive/u/0/folders/1dhf6oudh4GuJz6flxoHtzR7dWcu8NQBR). It would be great to re-record such a video and, if possible, add it to the Docs & Readme.