New "template" style example game

Instead of the rather specific Lätkäzombit-adventure, the example game that comes with the engine could a very plain "template" adventure, without story, real characters and just "insert witty retort here" -style texts. All the features should be featured, of course.

Start by locating the current Lätkäzombit-adventure example and reviewing how it exercises the engine. Replace it with a plain template adventure that showcases all engine features without a specific story or real characters; completion means the new example is functional and covers the feature set.

Written by the indexing model from the issue text.