jeje22

feat: add logging option

1

This PR enable logging when the flag `-logging` is set to true. This feature will logs the body of the request, i.e.: 2020/05/18 16:20:50 incoming request with BODY: {"dd"}

[BUG] Advanced functions causes SyntaxAnalysisException

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**Describe the bug** I am using AWS OpenDistro 7.10 with SQL queries. Using advanced functions in select clause gives SyntaxAnalysisException whereas simple functions works. **Example** Working example: - `SELECT DATE_FORMAT(data.timestamp,...