engine: Addition to ReplacementUtils

This patch adds enhancement to ReplacementUtils which enables to select a
separator for the list of items to show, and to provide the maximum number
of items to show in replaceWith function.

Change-Id: I77f64b31b69574aff68a0706dd7d6afa3037511a
Signed-off-by: Amit Aviram <aaviram@redhat.com>