Query parser errors need more graceful handling about bitfunnel HOT 1 OPEN

The referenced PR ensures that ParseError exceptions are caught and therefore do not crash the engine. The query result (Instrumentation) reflects whether the query was successfully run.

The work that remains:

• Return exception diagnostic error message as part of the query's Instrumentation results.
• Treat a single-term phrase in a query as a unigram term rather than an error (a comment in QueryParser::ParsePhrase shows one way to do this).

One approach to including the parse error message as part of query results:

• Add a field to QueryInstrumentation that holds either a ParseError message or nullptr
• Capture this error in results as part of catching the exception
• Format this field to any outputted CSV file in a new column
• De-allocate the error message data when QueryInstrumentation data is destroyed

from bitfunnel.