[Network modifications] Wrap CreateCouplingDevice.

[colinepiloquet]

Signed-off-by: Coline PILOQUET [email protected]

Please check if the PR fulfills these requirements (please use '[x]' to check the checkboxes, or submit the PR and then click the checkboxes)

• [x] The commit message follows our guidelines
• [x] 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 ? If so, link to this issue using '#XXX' and skip the rest No.

What kind of change does this PR introduce? (Bug fix, feature, docs update, ...) Wraps createCouplingDevice from powsybl-core to create a coupling device given two busbar section ids.

Other information: For now, I did not write the documentation. I will create a dedicated PR with fixes, and documentation about all the network modification as it will be clearer to explain. (branch creation, voltage level creation from scratch + this PR)

[EtienneLt]

Could you add some documentation in network.rst ? I think it is missing