TMDM-7573: "The 'concatenate' survive rule in t-swoosh should receive a separator as parameter"

Adds support for an optional parameter for concatenate rule in t-swoosh.
Fixes comparison issue when comparing many records survived using concatenate survivorship (comparison between merged value and single values).
Adds unit test case for feature.
(https://jira.talendforge.org/browse/TMDM-7573)