Update powsybl-core dependency

[rolnico]

Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

Does this PR already have an issue describing the problem?

No

What kind of change does this PR introduce?
Dependencies upgrade

What is the current behavior?
HPC uses powsybl-core 4.1

What is the new behavior (if this is a feature change)?
powsybl-parent is bumped to v18
HPC uses powsybl-core 6.3.0
Java version is specified and switched to Java 17
junit version is specified (5.10.1)
Mockito is bumped to 5.10.0.

Does this PR introduce a breaking change or deprecate an API?

• The Breaking Change or Deprecated label has been added
• The migration guide has been updated in the github wiki (What changes might users need to make in their application due to this PR?)

Other information:

[rolnico]

Warning : slurm integration tests must be done locally, using a server with SLURM installed

[olperr1]

Could you add an explanation for the disabled tests?

-@Disabled
+@Disabled("Slurm integration tests must be run locally.")

[olperr1]

I think it would be best to revert using powsybl-core 6.2.2 because of the CGMES import performance issue.

[rolnico]

I think it would be best to revert using powsybl-core 6.2.2 because of the CGMES import performance issue.

Done

[sonarqubecloud]

Quality Gate failed

Failed conditions
45.5% Coverage on New Code (required ≥ 80%)

See analysis details on SonarCloud

[olperr1]

There's still a problem with the test coverage, but appart that it seems ok to me.