FEATURE: create/modify a viewpoint (see #92)

[perfectstrong]

Content

By using Outliner from #69, this upgrade allows user to:

• Create a new viewpoint by clicking a button in Portfolio. Test included.
• Consult and modify topics (editing, dragging & dropping, removing from viewpoint). Test not included yet.

Close #92.

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Checklist

Please check that your pull request is correct:

• Each commit:
  • corresponds to a contribution that should be notified to users,
  • does not generate new errors or warnings at compile or test time,
  • must be attributed to its real authors (with correct GitHub IDs and correct syntax for multiple authors).
• The title of a commit should:
  • begin with a contribution type
    • FEATURE for a behaviour allowing a user to do something new,
    • FIX for a behaviour which has been changed in order to meet user’s expectations,
    • TEST when it concerns an acceptance test,
    • PROCESS for a change in the way the software is built, tested, deployed,
    • DOC when it concerns only internal documentation (however it is better to combine it with the contribution that required this documentation change),
  • be followed by a colon (:) with one space after and no space before,
  • be followed by a title as short, as user-centered and as explicit as possible
    • If it is a feature, the title must be the user action (beginning with a verb, and please not manage),
    • If it is a fix, the title must describe the intended behavior (with should).
  • ends with a reference to the corresponding ticket with the following syntax:
    • (closes #xx) if xx is a feature ticket (and the commit is a complete implementation),
    • (fixes #xx) if xx is a fix ticket (and the commit is a complete fix),
    • (see #xx) otherwise,
• Each committed line is:
  • useful (it would not work if removed)
    • if it is a comment line, its information could not be conveyed by better variables and function naming, better code structuring, or better commit message,
  • related to this very contribution (feature, fix...),
  • in English (with the exception of Gherkin scenarios in French and resulting steps),
  • without any typo in variable, class or function names,
  • correctly indented (spaces rather than tabs, same number of characters as in the rest of the file).

[benel]

@perfectstrong, vous ne pouvez pas intégrer le code de l'Outliner comme si c'était le vôtre !
C'est le travail de @florianess (pull request #69), vous devez impérativement garder ses commits pour qu'on lui attribue la paternité de ce code.

[benel]

Each committed line is (...) in English (with the exception of Gherkin scenarios in French and resulting steps)

Merci d'adopter (dans tout le scénario) les traductions officielles des primitives d'Hypertopic : https://github.com/orgs/Hypertopic/teams/porphyry/discussions/1

[benel]

Each committed line is (...) useful (it would not work if removed)

Pas de différence claire avec la ligne modifiée (et encore moins en relation avec la livraison).