[FEA] Support sha2

[viadea]

I wish we can support sha2 function.

eg in spark-sql:

select sha2(c_customer_id,256) from tpcds.customer limit 3;

Not-supported-messages:

      ! <Sha2> sha2(cast(c_customer_id#3 as binary), 256) cannot run on GPU because GPU does not currently support the operator class org.apache.spark.sql.catalyst.expressions.Sha2

[sameerz]

We could leverage rapidsai/cudf#9215 , but could also implement the sha-2 algorithm in spark-rapids-jni.