Add repo to support jmxtools dependency

[jaimecasero]

I notice this library is manually downloaded and installed into local repo.

If we confirm is really required for this project, then i would add this repo to the list, so normal resolution is applied
`

        <id>datanucleus</id>

        <name>DataNucleus Releases</name>

        <url>http://www.datanucleus.org/downloads/</url>

        <releases>

            <enabled>true</enabled>

            <updatePolicy>never</updatePolicy>

        </releases>

        <snapshots>

            <enabled>true</enabled>

            <updatePolicy>never</updatePolicy>

        </snapshots>

    </repository>

`

[vetss]

@jaimecasero

jmxtools is needed for JSS7 project and the most probably is not needed for GMLC itself. We need to try to remove a referense of it from gmlc project.

This lib may not be present in any repo because of Oracle policy.

[FerUy]

Thanks @vetss for the feedback. Then, if I understood you properly, we don't need to add this repo in GMLC and may close this issue, right?

[vetss]

@FerUy I think we need to

1. care that no file refer to the lib (it may be because of GMLC refers to some SS7 libs that referes to the lib). We may be need to add some "exclude" etc
2. remove / do not add direct loading of the lib from CI task / referense to the repo
3. test CI task

[FerUy]

Thanks @vetss 👍
Will take care of this after finishing TelScale version job.