REVIEW: Ensure UTs do not need createrepo/mergerepo

https://issues.sonatype.org/browse/NEXUS-5800
https://bamboo.zion.sonatype.com/browse/NX-YUMF5

Dropped all UTs that are covered by ITs
Do not run createrepo/mergerepo (there were UTs that were running generate/merge metadata tasks but did not required the metadata for asserts)