Sharing PyLossless derivatives

[scott-huberty]

It has been suggested to more explicitly document how one can share their pyLossless derivative, and how others can used that derivative.

While telling others how to "share" their data is a bit out of scope for us IMO - I think that we could have some dedicated documentation on how to load pylossless derivatives.

Here is a proposal that I think achieves this.

1. Store our pylossless derivative sample data on OSF - which addresses Moving the example data out of the repository #211
2. Create a tutorial named something like "Load and use Pylossess outputs".
3. In this tutorial, use Pooch or MNE's data fetcher to download the Pylossless derivative sample data from OSF
4. Show users how to load the derivative. This might help with run_with_raw(raw) not saving derivatives by default #220
5. Show users how to define a RejectionPolicy config to clean the loaded data. Show them how to adjust that config to achieve the cleaned state that they want.
6. Link to this new tutorial from the current tutorial, for users who want to learn how to do more than apply the default rejection policy to their data.

I think that the outlined proposal would address this issue and #223