DATE column type support

[dtjm]

Hello, I've already discussed this with @twdsilva, but while doing some evaluation with Kudu and the Calcite Adapter we found DATE support missing and causing this error on queries against tables which have DATE columns:

0: jdbc:kudu:schemaFactory=com.twilio.kudu.sq> SELECT * FROM "foo" LIMIT 1;
Error: Error while executing SQL "SELECT * FROM "foo" LIMIT 1": Unable to implement EnumerableLimit(fetch=[1]): rowcount = 1.0, cumulative cost = {1101.0 rows, 1102.0 cpu, 0.0 io}, id = 156
  KuduToEnumerableRel: rowcount = 1000.0, cumulative cost = {1100.0 rows, 1101.0 cpu, 0.0 io}, id = 154
    KuduQuery(table=[[kudu, foo]]): rowcount = 1000.0, cumulative cost = {1000.0 rows, 1001.0 cpu, 0.0 io}, id = 125 (state=,code=0)

DDL statements using DATE fail in this manner:

Caused by: java.lang.UnsupportedOperationException: Datatype is not supported DATE
	at com.twilio.kudu.sql.SqlUtil.getKuduDataType(SqlUtil.java:85)
	at org.apache.calcite.sql.SqlColumnDefNode.<init>(SqlColumnDefNode.java:57)
	at com.twilio.kudu.sql.parser.KuduSqlParserImpl.ColumnDef(KuduSqlParserImpl.java:1203)
	at com.twilio.kudu.sql.parser.KuduSqlParserImpl.ColumnDefList(KuduSqlParserImpl.java:1232)
	at com.twilio.kudu.sql.parser.KuduSqlParserImpl.SqlCreateTable(KuduSqlParserImpl.java:1075)
	at com.twilio.kudu.sql.parser.KuduSqlParserImpl.SqlStmt(KuduSqlParserImpl.java:926)
	at com.twilio.kudu.sql.parser.KuduSqlParserImpl.SqlStmtEof(KuduSqlParserImpl.java:964)
	at com.twilio.kudu.sql.parser.KuduSqlParserImpl.parseSqlStmtEof(KuduSqlParserImpl.java:205)
	at org.apache.calcite.sql.parser.SqlParser.parseQuery(SqlParser.java:153)

from a DDL statement similar to this:

CREATE TABLE IF NOT EXISTS foo (
	processed_date DATE NOT NULL
	PRIMARY KEY (processed_date)
)