[MNG-7768] Don't abuse RepositorySystemSession and other Resolver classes in Maven Core

**[Michael Osipov](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=michael-o)** opened **[MNG-7768](https://issues.apache.org/jira/browse/MNG-7768?redirect=false)** and commented

As noticed in [this PR](https://github.com/apache/maven/pull/1092) `maven-core/src/main/java/org/apache/maven/plugin/internal/DefaultPluginValidationManager.java` abuses `RepositorySystemSession` and `ConfigUtils` for convenience reasons. Those classes are unrelated and should feed from `MavenSession` since they don't interact with the repo system at all.

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**Affects:** 3.9.1

**Issue Links:**
- [MNG-7810](https://issues.apache.org/jira/browse/MNG-7810) Provide a SPI for the v4 api
(_**"requires"**_)