[PPL-Lang] Support CAST command

[qianheng-aws]

Is your feature request related to a problem?
Support CAST command.

`cast(expr as dateType)` cast the expr to dataType. return the value of dataType. The following conversion rules are used:

+------------+--------+--------+---------+-------------+--------+--------+
| Src/Target | STRING | NUMBER | BOOLEAN | TIMESTAMP   | DATE   | TIME   |
+------------+--------+--------+---------+-------------+--------+--------+
| STRING     |        | Note1  | Note1   | TIMESTAMP() | DATE() | TIME() |
+------------+--------+--------+---------+-------------+--------+--------+
| NUMBER     | Note1  |        | v!=0    | N/A         | N/A    | N/A    |
+------------+--------+--------+---------+-------------+--------+--------+
| BOOLEAN    | Note1  | v?1:0  |         | N/A         | N/A    | N/A    |
+------------+--------+--------+---------+-------------+--------+--------+
| TIMESTAMP  | Note1  | N/A    | N/A     |             | DATE() | TIME() |
+------------+--------+--------+---------+-------------+--------+--------+
| DATE       | Note1  | N/A    | N/A     | N/A         |        | N/A    |
+------------+--------+--------+---------+-------------+--------+--------+
| TIME       | Note1  | N/A    | N/A     | N/A         | N/A    |        |
+------------+--------+--------+---------+-------------+--------+--------+

Cast to **string** example:

    os> source=people | eval `cbool` = CAST(true as string), `cint` = CAST(1 as string), `cdate` = CAST(CAST('2012-08-07' as date) as string) | fields `cbool`, `cint`, `cdate`
    fetched rows / total rows = 1/1
    +---------+--------+------------+
    | cbool   | cint   | cdate      |
    |---------+--------+------------|
    | true    | 1      | 2012-08-07 |
    +---------+--------+------------+

See details in this doc: https://github.com/opensearch-project/opensearch-spark/blob/v0.6.0/docs/ppl-lang/functions/ppl-conversion.md#ppl-type-conversion-functions

What solution would you like?
We already have ANTLR definition here:

opensearch-spark/ppl-spark-integration/src/main/antlr4/OpenSearchPPLParser.g4

Line 544 in 90171f3

dataTypeFunctionCall

Need to implement its parser and convert it to Spark function Cast