The multi-model JSON file names in the tutorials folders are deprecated.

Inside the different folders inside Multi-models\X\ there should be a mm.json file.
In the tutorials folders we still have a file named X.mm.json

There was always a warning related to this... But we want to remove it and deprecate the previous file name convention.

For starters we made the warning more understandable. Example:

```
Found deprecated style mm at: into-cps-projects/tutorial_1/Multi-models/Non-3D/Non-3D.mm.json

Consider renaming: Non-3D.mm.json to: mm.json
```

After upgrading all tutorials and examples we can move towards deprecation.

Search the tutorial and example folders under Multi-models for files using the old X.mm.json naming convention, and review the warning example in the issue. Rename each affected file to mm.json; the work is complete when the old filenames no longer remain in those folders.

Written by the indexing model from the issue text.