Changes to Theme values and icons

[mradamcox]

We need to change a few things on the frontend about themes, may as well do them all at once. See search/helper/iconMatch and search/helper/themeIcons for many of these chagnes.

• Change the "Food Access" icon to MUI ShoppingCart
• We are currently associating the AutoAwesomeMosaic with any result items that have more than one theme. We need to change this so that instead, if an item has multiple themes, the icon for the first them is used (later we will add some alteration to the icon that indicates multiple themes are present).
• We need to add a new theme option, "Composite Index", and for this theme associate the AutoAwesomeMosaic