NEXUS-5584: Atomic config file writes

Changes for:
* nexus.xml
* capabilities.xml
* logback.properties and logback.xml and all participant XMLs
* security.xml and security-configuration.xml

Issue:
https://issues.sonatype.org/browse/NEXUS-5584

CI:
https://bamboo.zion.sonatype.com/browse/NX-OSSF26-1