Add: Pack bucket and lazy writing indexes

Merged Akshay Bharambe requested to merge fdb_feature_special_bucket into devbranch
  1. Add: Pack bucket and lazy writing indexes
  2. Fix: Atomic file not updated, Hard link issue.
  3. Add: Create temp directory if not present at app root.
  4. Fix: Bucket id generated for an existing bucket.
  5. Fix: Data not updated by provided single primary key in the compound index.

https://corelab.mkcl.org/MKCLOS/coreosv3/coresls/issues/4

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