Optimize Indexes support

[apoorvedave1]

Describe the issue

Blocked by #29
Once hyperspace has an incremental indexing support, add support for optimizing indexes. This would pick parts of indexes which are made of large number of small files, and combine/compact them into small number of large files. This would improve the performance of the index since the number of index files would be greatly reduced

To Reproduce

NA

Expected behavior

hyperspace.optimize(indexName) would update indexes to improve their performance

Environment

NA

[apoorvedave1]

duplicate of #111