Add support for Timestamp data type in SQL Select (#7185)

This change adds support for casting strings to Timestamp via CAST:
`CAST('2010T' AS TIMESTAMP)`

It also implements the following date-time functions:
  - UTCNOW()
  - DATE_ADD()
  - DATE_DIFF()
  - EXTRACT()

For values passed to these functions, date-types are automatically
inferred.

pkg/s3select/json/record.go

@@ -60,6 +60,8 @@ func (r *Record) Set(name string, value *sql.Value) (err error) {
 		v = f
 	} else if i, ok := value.ToInt(); ok {
 		v = i
+	} else if t, ok := value.ToTimestamp(); ok {
+		v = sql.FormatSQLTimestamp(t)
 	} else if s, ok := value.ToString(); ok {
 		v = s
 	} else if value.IsNull() {