Rename WILDCARD_ENABLED flag #200
Description
The WILDCARD_ENABLED environment variable is used for the Cloud Function serving the Review environment, and it has been causing some confusion.
We could name it REVIEW_PREVIEW (as suggested by Leo), or something like USE_SUBDOMAIN_AS_CONTENT_PATH_PREFIX to describe the effect. For the other effect, disabling caching, we could introduce a separate environment variable like CACHE_DISABLED.