Currently it is necessary for a store to become available before `connection-attempts` are exceeded, otherwise cache startup fails. It should be possible for the PM to still start without the store being available, with the store's unavailability logged and operations requiring persistence still throwing StoreUnavailableException messages unless `SKIP_CACHE_STORE`/`SKIP_CACHE_LOAD` flags are present.

Cache startup should still fail if preload=true as this behaviour is not possible if the store is unavailable.