Staging move for Maven checks unnecessary maven metadata

ISSUE:

It looks like moving one GAV with the staging API triggers checking all maven metadata in the same group.
Each check is fast (20 ~ 30 ms) but when there are a few thousands GAVs in the group, the staging API can take a few minutes or more to complete.

REPRODUCE STEPS

1. Create two hosted repositories: maven-hosted and maven-releases
2. Generate dummy data (please check 55985_prepare.sh )
3. Enable DEBUG logging for "org.sonatype.nexus.repository.maven.internal"
4. Move only one version 1.8:

   curl -D- -u admin:admin123 -X POST 'http://localhost:8081/service/rest/v1/staging/move/maven-releases?repository=maven-hosted&maven.groupId=test.example55985&maven.artifactId=my-app1&maven.baseVersion=1.8'

EXPECTED BEHAVIOUR:

In the nexus.log, not many DEBUG logging line: org.sonatype.nexus.repository.maven.internal.hosted.metadata.MetadataBuilder - -> GAbV: ...
Or, if this check is necessary, it should be checked parallely.

ACTUAL BEHAVIOUR:

It checked 26 GAVs:

$ grep -E 'qtp887917427-129.+MetadataBuilder - -> GAbV' ./sonatype-work/nexus3/log/nexus.log -c
26