[slides] add biomineralization slides

slides/biomin.md

slides/img/biomin_exercise-setup.png

slides/img/biomin_exercise-setup_small.png

slides/img/biomin_intro-microbes.png

slides/img/biomin_introCementedSand.jpg

slides/img/biomin_introColumns.png

slides/img/biomin_introPoroPermFelix.png

slides/img/biomin_introSegmented.png

slides/img/biomin_model-2p.png

slides/img/biomin_model-2pnc.png

slides/img/biomin_model-clogging.png

slides/img/biomin_model-microbes.png

slides/img/biomin_model-precipitation.png

slides/img/biomin_model-urea.png

slides/index.md