Merge Text/Lucene search branch into develop

[Ashvin A <aa...@gmail.com>]

Hi,

As part of GEODE-11, we added ability to create Lucene indexes and execute
text search queries on GEODE Regions. Currently, we have implemented the
core classes and a basic end-to-end flow. We think it is a good time to
introduce this feature to the community and let the use cases drive future
development. With this intention, we plan to merge GEODE-11 into develop
branch. Additional details can be found on the wiki:
https://cwiki.apache.org/confluence/display/GEODE/Text+Search+With+Lucene.

Key points:

   1. Geode-Lucene connector creates lucene indexes asynchronously (using
   async queues). The indexes are stored back in "hidden" Geode Regions. The
   async queue listener is not added till a lucene index is create and linked
   to a Region.
   2. Like Region data, indexes are distributed and persisted (if needed).
   Search queries use functions to execute parallel search.
   3. Lucene index management code is part of a new module gemfire-lucene.
   Gemfire-core does not depend or use any of the features in lucene. User has
   to add the jar to classpath and use experimental api to "activate" lucene
   code.
   4. The code has good unit test coverage (>85%)

What is pending?

   1. Deep integration: Gfsh, REST, CQ, Spring etc
   2. Search stats and result normalization
   3. Performance testing and fixes
   4. Support for replicated regions

Code review link: https://reviews.apache.org/r/40097/

Any suggestions?

Thanks,
Ashvin