(cherry picked from commit 8567bcd3)

New option to decide whether the user should be asked for confirmation when an entry is being deleted.

BUG: 463675
FIXED-IN: 23.03

(cherry picked from commit 6332860f)

Support different plot file formats (PDF, SVG and PNG) also for Maxima and removed the JPEG option for Octave since the quality is very bad.

In the context menu of result items keep only those entries that are relevant for the results (save result, etc.) and not all entries that are relevant for the actual command. 

In case of conflict in i18n, keep the version of the branch "ours"
To resolve a particular conflict, "git checkout --ours path/to/file.desktop"

* render PDF content to QImage via poppler in ImageResult
* when saving the plot images, allow to save in the original format only (pdf should be stored as pdf, etc.)
* added pdf to the list of supported extensions for Octave, further backends will follow.

[octave] simplified the printing of plot images and use the same default size of the plot as in maxima - 500x340 pixels (will be made configurable soon).

Removed some debug output in TextResult having toHtml() call that can become very expensive for bigger outputs.

In 30476363 the call of updateGraphicPackagesFromSettings() was removed. This solved some issues but has broken the embedded plots.
Restoring the old and working logic in Octave code that we had before that "graphics packages" code was merged.

Show the dimensions of a variable (number of rows and columns) in the variable panel, implemented to Octave first.