Improve presentation of errors from Nexus

[szpak]

For example:

> Task :closeSonatypeStagingRepository FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':closeSonatypeStagingRepository'.
> Failed to close staging repository, server at https://oss.sonatype.org/service/local/ responded with status code 500, body: io.github.gradlenexus.publishplugin.shadow.okhttp3.ResponseBody$1@1ac212a0

Might potentially show the body (if text/json) and maybe we could even try to determine that credentials were not provided.

[gmazzo]

This other plugin does a good job reporting logs from Nexus, printing all validation rules, reasons of failure, etc. https://plugins.gradle.org/plugin/name.remal.maven-publish-nexus-staging

May be you can join forces with them too for this