Update themes that reference Morpho

[jeanetteclark]

Describe the feature you'd like

The release of Metacat 3.0.0 means that Morpho will no longer work on any node. We need to update the themes to at a minimum remove references to Morpho. We could also consider whether we want/need to include warnings in FAQ pages or the like about how Morpho no longer works.

From this search it doesn't seem like there are too many references to remove so shouldn't be too bad.

[artntek]

related to NCEAS/metacat#1914 (comment)