#704: Remove remaining ArtifactRepository leftovers + use version range for VersionsHelper where applicable

[andrzejj0]

Utilising the fact that we can pass the versionRange directly to RepositorySystem.resolveVersionRange, which should optimise the search process (possibly less lookups performed).

Also, removing the unused findLatestVersion( Artifact, VersionRange, Boolean, boolean ) method.

[andrzejj0]

I've noticed that there are still some ArtifactRepository leftovers left. Removed those.

Also, Maven 3 version range resolver allows version range resolving -- using that to speed up version resolution a bit.

Small refactoring/cleanup, especially in DisplayPluginUpdates.

Oh and by the way -- as you can probably see, there are still some parts where we are accounting for Maven 2. Should we remove that? If so, I'll do that in another PR, because that would involve also removing some of the IT's.

@slawekjaranowski please check

[andrzejj0]

@slawekjaranowski

As advised in https://cwiki.apache.org/confluence/display/MAVEN/Plugin+migration+to+Maven3+dependencies

Remove maven-compat (or give it the test-scope if it is required by the maven-plugin-testing-harness)

[andrzejj0]

I guess I can move to PlexusJunit4TestCase in another PR.

[slawekjaranowski]

prerequisites is only used for maven-plugin packaging.

[slawekjaranowski]

I start thinking to introduce spotless as is done in Maven from parent poms 38 when we have such line changed 😄