Support using grouping keys that are functions in the select clause

[vpapavas]

Describe the bug
This query fails

ksql> CREATE TABLE test2 AS SELECT INITCAP(COL1), COL2, TRIM(COL3), concat(initcap(col1), col2, trim(col3)) AS foo, COUNT(*) FROM input3  GROUP BY INITCAP(col1), col2, TRIM(col3);
Non-aggregate SELECT expression(s) not part of GROUP BY: CONCAT(INITCAP(COL1), COL2, TRIM(COL3))
Either add the column to the GROUP BY or remove it from the SELECT.

The problem is that the AggregateAnalyzer does not recognize that the arguments of function CONCAT in the SELECT clause are actually grouping keys.

To Reproduce
Steps to reproduce the behavior, include:

1. The version of KSQL.
   master
2. Sample source data.

CREATE STREAM input3 (id INT KEY, col1 VARCHAR, col2 VARCHAR, col3 VARCHAR, col4 VARCHAR) WITH (kafka_topic='input', value_format='json');

3. Any SQL statements you ran

Expected behavior
The query succeeds

Actual behaviour

Non-aggregate SELECT expression(s) not part of GROUP BY: CONCAT(INITCAP(COL1), COL2, TRIM(COL3))
Either add the column to the GROUP BY or remove it from the SELECT.

[agavra]

I think the above PR fixes this, closing out this ticket as bookkeeping