New dumux messages

It would be nice to have a larger variety of messages at the start and the end of Dumux simulations. The current messages can be found in dumuxmessage.hh and could be extended by additional entries. Possible entries can be quotes from pop culture (movies, books...) which might be applied to Dumux in a funny or also philosophical manner. Of course, quotes from real persons can also be added. Suggestions and ideas are very welcome!
See !3745 (merged)