[MNG-8002] Allow to bypass mirror for SNAPSHOT resolution

**[Konrad Windszus](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=kwin)** opened **[MNG-8002](https://issues.apache.org/jira/browse/MNG-8002?redirect=false)** and commented

Currently the [mirror settings](https://maven.apache.org/guides/mini/guide-mirror-settings.html) in `settings.xml` only allows to either mirror everything with a wildcard or exclude/include specific repository ids.
Such an exclude/include list is currently hard to maintain. To better support use cases where the RELEASE version is available in Maven Central (often supposed to be mirrored) but the according SNAPSHOT is in another repo (OSSRH, Apache, Eclipse, GitHub, Azure, ....) it would be beneficial to also allow to bypass the mirror for SNAPSHOT requests and instead use the repositories defined inside the pom.xml.

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No further details from [MNG-8002](https://issues.apache.org/jira/browse/MNG-8002?redirect=false)