Handle ConnectionUsage as Edge in SysON

[adaussy]

This issues aims to provides a subset of the feature defined in #1104

Only the simple edge representation will be handled (no direction displayed at the end of the edges):

It will be possible to create/reconnect the edge from:

• PartUsage node
• ItemUsage node
• ItemUsage borderedNode

On the centered label will be displayed the name and the type of the ConnectionUsage. The user will be able to edit those two properties.

[AxelRICHARD]

What will happen when the tool will be executed?
It will create:

1. the "connect part1 to part2"
2. the "connect part1 to part2" inside a ConnectionUsage named connection1
3. the "connect part1 to part2" inside a ConnectionUsage named connection1 and a ConnectionDefinition?
4. Something else?

In case the answer above is 1 or 2, what will happen when the user will edit the label and set the type of the ConnectionUsage? Imagine the type is not compatible with part1 and part2, what will happen?

[AxelRICHARD]

The answer to previous question is answer #2.
Then when user will edit the label and set the type of such ConnectionUsage, it will set the ConnectionDefinition even if this ConnectionDefinition is not compatible.
The validation rules are there to warn users about that.