Add support to contribute a new diagram style and contribute a SVG node style

[lfasani]

Expected behavior

The aim is to contribute a new style that is not included in the sirius-component core
There will be two kind of changes:

• enhance sirius-component to support contributed node style
• contribute a new style based on a provided SVG

Cuttings backs

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Potential side effects

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Describe alternatives you've considered

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