ST6RI-781: Show multiplicities in nodes (PlantUML)

[himi]

This PR supports rendering multiplicities in nodes. So far the visualizer renders multiplicities in edges only. I added three new styles:

• NODEMULTIPLICITY Show multiplicities in nodes.
• EDGEMULTIPLICITY Show multiplicities in edges.
• IMPLICITMULTIPLICITY Show implicit multiplicities as well. That means even if you do not explicitly specify multiplicities, the visualizer renders default multiplicities.

If you do not specify any styles, view choose proper multiplicity rendering. For example, Tree view shows multiplicities in nodes by default.

[himi]

This is just an example with Tree view:

package Vehicle {
    part def Vehicle {
        part tire[*];
    }

    part car : Vehicle {
        part :>> tire [4];
    }
    part bicycle: Vehicle {
        part :>> tire[2];
    }
    part unicycle: Vehicle {
        part :>> tire[1];
    }
}

This is rendered as below: