common, os, osd, test, tools: FileStore must work with ghobjects rather than hobjects

common, os, osd, test, tools: FileStore must work with ghobjects rather than hobjects

Add ghobject_t to hboject.h header
Add constants NO_SHARD/NO_GEN and change gen_t/shard_t
Convert other headers from hobject_t to ghobject_t
Mostly straight hobject_t to ghobject_t for src/os cc files
Fix tools and tests and enable ceph-dencoder
Add filename generation and parsing including unittest addition
Get ceph-filestore-dump to build
Add gen/shard to DBObjectMap::ghobject_key() and update test case
Add CEPH_FS_FEATURE_INCOMPAT_SHARDS new FileStore feature
Add CEPH_OSD_FEATURE_INCOMPAT_SHARDS new osd feature

Fixes: #5862
Signed-off-by: David Zafman <david.zafman@inktank.com>