Fixing Tableau Extract Error

[lyndonbauto]

Summary

Fixing Tableau Extract Error

Description

[1] Fixed some logic around connection pooling.
[2] As discussed with Alexey, this is non-trivial to test and we will brainstorm a way to test this on Monday after GA release. For now we will rely on manual testing done by Yang, Alexey and Lyndon using Tableau.

Connection pool within TinkerPop was the connection pool that was throwing an exception.
SqlGremlinQueryExecutor held a static SqlConverter, which was given a GraphTraversalSource upon instantiation. This was then used to run Traversals as they came.
Close function would then close that GraphTraversalSource on the SqlGremlinQueryExecutor, so next query comes along and TinkerPop (library that implements GraphTraversalSource) would throw an exception saying that their connection pool is shutdown.
Close still closes the GraphTraversalSource (because it should), but now each query gets a fresh GraphTraversalSource to work off of, and it is regenerated if it is closed, then invoked again

Related Issue

https://bitquill.atlassian.net/browse/AN-879

Additional Reviewers

@birschick-bq
@lyndonb-bq
@xiazcy
@simonz-bq
@alexey-temnikov
@kylepbit