Consistently use platform independent line separator

kpauls, as discussed offline SLING-10268 will introduce platform independent line separators for all generated repo-init statements. However, the converter code base seems to have a difficult history with line separators:

• originally they seemed to be mostly platform-independent but tests were not
• test got fixed with https://github.com/apache/sling-org-apache-sling-feature-cpconverter/commit/6c2ef9929c3e12acf4b7b104871816a6e3e15f4e
• then with SLING-10121 platform independent separators got replaced by \n https://github.com/apache/sling-org-apache-sling-feature-cpconverter/commit/86b412dffc2c9c5654745f5ab1946d758b11004a

IMHO going with platform independent separators would be better.... so, i would suggest to revert tests back and fix any potential remaining usages of \n in the code base. wdyt?