Initial version

[flo-dup]

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

• 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?
First version

What is the current behavior?
Nothing

What is the new behavior (if this is a feature change)?
First version generating a network area diagram, colouring the voltage level nodes according to their nominal voltage and adding the number of buses inside.

[geofjamg]

Maybe we can merge this PR to have an intial simple version of the component to avoid letting main branch empty :-)
For me just 2 things to do:

• move layout from SLD
• add more parameters checks like null checks in many places

[geofjamg]

Maybe we can merge this PR to have an intial simple version of the component to avoid letting main branch empty :-) For me just 2 things to do:

* move layout from SLD

* add more parameters checks like null checks in many places

And a README with a code sample!