Allow to bend lines in NAD

[So-Fras]

Describe the current behavior

It is not possible today to bend lines in network-area diagrams.

Describe the expected behavior

The user is able to bend lines in network-area diagrams.

Describe the motivation

• Enhance readability
• Allow more customization of the layout

Extra Information

No response

[flo-dup]

First step:

• only for lines (not transformers)
• only for non-parallel lines (no fork)
• only one point: just moving the middle point which already exists
• disabled if interactivity disabled
• the callback is on all the half-lines
  • when clicking on the line the middle point moves where the mouse is
  • and then follows the mouse pointer
• position should be contained in the metadata
• powsybl-diagram should be able to have these coordinates as layout input (this should probably be skipped though to avoid changing again powsybl-diagram input after next step)

[flo-dup]

Second step to have in mind while coding first step:

• same base restriction: for non-parallel lines, not for transformers
• BUT not reusing the middle point:
  • a new point is created where the mouse is clicked
  • the middle point new position is calculated and moved
• a small square needs to be displayed where the new point is, to be able to move again that point; this square should be hidden if interactivity is disabled
• again, positions should be contained in the metadata
• powsybl-diagram should be able to have these coordinates as layout input