COVID Information link and CARA@CERN section only for CERN theme
Closes https://gitlab.cern.ch/cara/cara/-/issues/209 and https://gitlab.cern.ch/cara/cara/-/issues/217
theme
concept elevated to the apps
directory, rather than it being at the calculator one.
Due to the new file structure, changed the path for CARA_THEME
to value: cara/apps/templates/cern
.