Add Memory gatekeepers for InMemoryResultSet to prevent any OOM on lens server

In Some cases operations on InMemoryResultSet can result is high memory usage on LensServer

1. InMemoryResultSet.toQueryResult() is done for a huge result
2. lens.query.prefetch.inmemory.resultset.rows = Huge Number .

In both cases we need to have some gate keeping as these features can be accessed/configured by users