Moved ListDelimiterHandler classes to convert package.

The topic of list delimiter handling is related to data type conversion.
Also, some functionality for detecting containers (arrays, collections, ...)
can be reused for some conversions.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1512796 13f79535-47bb-0310-9956-ffa450edef68