pom clean-up and plugin version updates

- only use properties for dependencies with multiple artifacts
-- lucene
-- jersey

- updated plugin versions:
-- scala-maven-plugin: 3.1.5
-- maven-compiler-plugin: 3.1
-- maven-surefire-plugin: 2.14.1
-- maven-enforcer-plugin: 1.2
-- maven-install-plugin: 2.4
-- maven-assembly-plugin: 2.4
-- org.vafer: 0.8