Once the primary remaining consumer of the parsoid endpoints in RESTbase (namely PCS) has been switched to using MW core endpoints, we can and should turn off pre-generation and caching for the parsoid endpoints in RESTbase.
NOTE: we could do this even while T339865 hasn't been implemented: since the parsoid endpoints in core are backed by the parser cache, just proxying their response should be fast enough.
NOTE: We probably still need purge events for the edge caches. Or can we just use a low fixed TTL? Public callers of the API should migrate to the core endpoints anyway.
NOTE: Turning off pre-generation for parsoid in RESTbase means we are no longer doign any parsing (and caching) on the MediaWiki parsoid cluster either. This means that all of the parsing will need to happen on the jobrunner cluster. To test out how much load this will generate, we can turn off cache writes in the MediaWiki parsoid endpoints by tweaking the TemporaryParsoidHandlerParserCacheWriteRatio setting.
