Add data files and model mask to sea ice metrics

[acordonez]

This PR accomplishes four things:

1. Adds a data file to the output bundle that includes the time mean sea ice and climatology.
2. Fixes a bug where the land sea mask was not applied to models.
3. Reports the MSE for the climatology without the mean included
4. Changes the y-axis settings on the output figure

[lee1043]

@acordonez thanks for the PR, I am running demo 9 notebook with this PR.

[lee1043]

@acordonez I checked the demo 9 notebook runs without error. But considering the graphics changed with the PR, could you please also update the notebook? Or I can also help update, let me know.

[acordonez]

@lee1043 Yes I can rerun the notebook.

[acordonez]

@lee1043 I pushed the notebook