For now, rend_cache_entry_t has been moved from or.h to rendcache.h and
those files have been added to the build system.
In the next commit, these will contain hidden service descriptor cache ABI
and API for both client and directory side. The goal is to consolidate the
descriptor caches in one location to ease development, maintenance, review
and improve documentation for each cache behavior and algorithm.
Signed-off-by: David Goulet <dgoulet@ev0ke.net>
