Resolve "Deprecate PlotCreator auto detection"

What does this MR do?

This MR deprecates the ExternalPlotCreator's auto-detection via the plot function signature, as this is very unstable and hard to maintain.

It will be removed in %Version 0.11 .

Can this MR be accepted?

• Added the deprecation warning
• Tests added or adjusted
• Pipeline passes
• Changelog entry added and version bumped

Anything to double-check?

Nope.

Related issues

Closes #100 (closed)