Improved styling of skill tables

When comparing different model runs using the skill table, sometimes it would be great to have finer-grained control over the color-coding. One example could be that you have one outlier (e.g. rmse=800) that ruins the color coding - you would have want to have it capped at 100. With matplotlib you can often do this normlization with the vmin and vmax keywords but that does not work - eventhough style accepts these kwargs.

Start by locating the skill-table implementation and the styling path that accepts keyword arguments, then compare its color normalization with matplotlib's vmin and vmax behavior. Verify the change with a skill-table example containing an outlier, ensuring explicit bounds cap the color scale while the table still renders correctly.

Written by the indexing model from the issue text.