Placement of newly opened Component Browser when nodes are selected

[akavel]

Pull Request Description

When a new node is created with the TAB key or by clicking the (+) on-screen button while multiple nodes are selected, place the new node below all the selected nodes. (Previously, the new node was placed below the node that was selected earliest.)

Additionally, when placing a new node below an existing non-error node with a visualization enabled, place the new node below the visualization. (Previously, the new node was placed to the left of the visualization.)

https://www.pivotaltracker.com/story/show/180887079

Visuals

The following screencast demonstrates the feature on various arrangements of selected nodes, with visualization enabled and disabled.

Screen.Recording.2022-03-24.at.18.02.25.mov

The following screencast demonstrates that new nodes created by double-clicking an output port of a node with visualization enabled are now placed below the visualization:

Screen.Recording.2022-03-25.at.11.52.35.mov

Important Notes

• Some refactorings that were needed for this PR were ported from the Placement of newly opened Component Browser dictated by the mouse pointer. #3301 PR:
  • the code responsible for calculating the positions of new nodes was moved to a separate module (new_node_position);
  • the free_place_finder module was made a submodule of the new_node_position module, due to the latter being its only user.

Checklist

Please include the following checklist in your PR:

• The documentation has been updated if necessary.
• All code conforms to the Scala, Java, and Rust style guides.
• All code has been tested:
  • Unit tests have been written where possible.
  • If GUI codebase was changed: Enso GUI was tested when built using BOTH ./run dist and ./run watch.

[wdanilo]

add this to the whole enum instead - will be clearner

[akavel]

(Process note: the code-review is now Approved, therefore the PR is waiting for an Acceptance/QA Review by @vitvakatu on Task https://www.pivotaltracker.com/story/show/180887079 before merge.)

Placement of newly opened Component Browser when nodes are selected - Pivotal Tracker