The generic packages recipe currently has no secrets support, but to port the FTL tests from Cirrus we need (currently) the FTL key (currently exposed in Cirrus as GCLOUD_FIREBASE_TESTLAB_KEY) and a Google Maps API key (currently exposed in Cirrus as MAPS_API_KEY).

We may need to add other API keys in the future, so I would like to continue the packages repo's general model of building things in generic way in the recipe, and then controlling the details from in-repo configuration.