[web] Removed ogs-5 link in navbar, added ogs-5 links to tutorials.

web/config.toml

web/content/_index.pandoc

web/content/books/computational-geotechnics-i.pandoc

...omputational-hydrology-i-groundwater-flow-modeling.pandoc

web/content/books/computational-hydrology-ii.pandoc

web/content/books/computational-hydrology-iii.pandoc

web/content/books/geoenergy-modeling-i.pandoc

web/content/books/geoenergy-modeling-ii.pandoc

web/content/books/geoenergy-modeling-iii.pandoc

...ontent/books/models-of-thermochemical-heat-storage.pandoc

web/content/ogs-5/index.pandoc