Decimal values are displayed as scientific notation in beeline

As we are using BigDecimal.toString() returns scientific notation instead of original text, which confuse customer. It should be changed to toPlainString() at here

https://github.com/apache/hive/blob/master/beeline/src/java/org/apache/hive/beeline/Rows.java#L165

Repro steps:

beeline> select cast(0 as decimal(20,10));
//output
0E-10