2.17 Christmas Version!

• Filer
  • Redis, Cassandra can support super large directories
  • Add HBase for filer store
  • Make path-specific stores portable by trimming out common prefixes
  • Add -defaultStoreDir so that filer.toml can be skipped #1659
• S3
  • Fix a bug causing loop with empty folders #1701
  • Fix bucket-specific Admin permissions