Remove ScalarType.isDateTimeCapable() ... (only used by CSV reader)

So the complexity cost doesn't justify itself against only being used
by CSV reader to validate when assigning a date/time format to a property
/ expression path.

ebean-api/src/main/java/io/ebean/plugin/ExpressionPath.java

@@ -45,12 +45,6 @@ public interface ExpressionPath {
    */
   Object parseDateTime(long systemTimeMillis);
 
-  /**
-   * Return true if the last type is "DateTime capable" - can support
-   * {@link #parseDateTime(long)}.
-   */
-  boolean isDateTimeCapable();
-
   /**
    * Return the underlying JDBC type or 0 if this is not a scalar type.
    */