Make a cleaner input format

Right now all adventure data are entered directly in the program, as a list of dictionaries. Not user-friendly, and not even fun to edit as a programmer.

Simple interface would involve parsing a text file of data:

```
Time PhysicalDifficulty Adventure Name
5 7 Picnic Rock
3 5 Beaver Lake
```

No files or tests are named. Start by locating where adventure data are currently defined and trace how the script consumes the list of dictionaries. Done means accepting equivalent rows from a text file and using them to generate the adventure matrix.

Written by the indexing model from the issue text.