[ferrighi]

This PR:

• adds some CSS to handle better space for layer names in the wms visualisation
• handles the legend url for thredds.met.no adding palette (a bit ad-hoc)
• handles update of legend when changing style
• handles loading of legend image in Solo theme.
• handles wms from MP8 and lower in the wms visualisation, not in the search map (see issue with ups_north_proj settings and initial projection setting #69 ). It will exclude visualisation button in the search map when init_proj is not 4326 and wms from ms8 is provided.

This has been tested on staging. Please do one more round of checks.