Get html titles to show up for notebooks (possibly drop metadata files?)

I just noticed something about the HTML of the tutorials that are getting generated: their title are "[]".  I've traced the root cause to this: the `nbconvert` html template gets the title from the 'name' attribute of the `metadata` of the `.ipynb` files, and currently that name is empty for the tutorials.

So the question, then, is how to best populate these.  It could be that `README` should just add as part of the instructions to add a useful name to the metadata. The downside to that is that it keeps real metadata in *two* places - the `.ipynb` file and the `metadata.cfg` file that lives alongside it.

Two alternative approaches:
* Add code to the build step of `setup.py` that either overwrites `name` in the `.ipynb` with whatever `link_name` is from `metadata.cfg`, or just overwrites the title in the generated html to match `link_name` (although both of those may be a bit hacky). 
* Dispense with `metadata.cfg` and instead just put that metadata in the `.ipynb` file - it would be pretty straightforward to modify `setup.py` to do this, as the `.ipynb` is just a JSON file.

@adrn, what do you think?