[MNG-8373] Extract resolver related code into its own impl submodule

**[Konrad Windszus](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=kwin)** opened **[MNG-8373](https://issues.apache.org/jira/browse/MNG-8373?redirect=false)** and commented

As https://github.com/apache/maven/tree/master/compat/maven-resolver-provider has a substantial amount of classes and also very limited interaction with other core classes, it would be good to re-extract the resolver related ones into a dedicated submodule. In the best case this would allow to get rid of all resolver dependencies (at least resolver-spi) from Core.

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This issue is a sub-task of [MNG-8338](https://issues.apache.org/jira/browse/MNG-8338)

Start by reviewing compat/maven-resolver-provider and identifying which classes are resolver-related and how they interact with Maven Core. Trace the resolver dependencies, especially resolver-spi, before planning the dedicated submodule. Done means the resolver code is isolated in that submodule and Core no longer needs those dependencies where possible.

Written by the indexing model from the issue text.