WB-1009: Log4j Appender for BigQuery

BigQueryAppender.java
-	Added "throws" in the constructor and createAppender()
-	Surrounded the call to insertTableData with try/catch.

Log4jTests.java
-	Add "throws" to loggingTest()

BigqueryRefresher.java
-	Updated exception handling

BigqueryUtils.java
-	Removed unnecessary methods and variables.
-	Added "throws" instead of catching any exceptions