Enable ordering for DruidScanQuery

[pm-src]

Code change needed:

in.zapr.druid.druidry.query.scan.DruidScanQuery.java

private String order;

@builder
private DruidCustomScanQuery(@nonnull DataSource dataSource, List virtualColumns, ..........
.......
Long limit, Boolean legacy, Context context) {
.
.
.
this.order = order;
if (order != null) {
Preconditions.checkArgument((order.equals("ascending") || order.equals("descending")),
"only order ascending or descending is supported");
}
.
.
.

}

}

[szymeker]

Ready for review #173