[FEAT] Provide more information for link event in BPMN Semantic data

[tbouffard]

Is your feature request related to a problem? Please describe.
Add link between the source/throw and target/catch links to continue the work started in #929.
This will help for process-analytics/bpmn-visualization-addons#20

Additional context
In [email protected], we probably don't store the information in the internal model, so implementing this feature may require to store more LinkEventDefinition attributes in the internal model (sources and target attributes).

IMPORTANT: this feature must be usable with Bonita, so we must ensure that the diagrams generated by Bonita provides the "link" information (source and target), otherwise, this issue is not a priority for 2023 Q3

✔️ The source property is set in the intermediateCatchEvent of diagrams exported by Bonita 2022.1.

Example: bonita_2022.1_link_events.bpmn.txt

    <model:intermediateCatchEvent id="_ukcP0F3kEe6_5KY6Wpc1-Q" name="Target Link 1">
      <model:linkEventDefinition id="_t2boY13mEe6_5KY6Wpc1-Q">
        <model:source>_t2boZV3mEe6_5KY6Wpc1-Q</model:source>
      </model:linkEventDefinition>
    </model:intermediateCatchEvent>
    <model:intermediateThrowEvent id="_xj6RoF3kEe6_5KY6Wpc1-Q" name="Link">
      <model:linkEventDefinition id="_t2boZV3mEe6_5KY6Wpc1-Q" name="target-link-1"/>
    </model:intermediateThrowEvent>

BPMN specification