Overhaul annotations UX

Create a new new annotation toolbar to replace the current one as discussed in the task T8076.
Fixes:
BUG: 386578
BUG: 374728
BUG: 352310
BUG: 330518
BUG: 341914
BUG: 157289
BUG: 358057
BUG: 412767
BUG: 413595
BUG: 420462
FIXED-IN: 1.11.0

Test Plan
Before testing this revision
Delete or Temporary move aside the following files:

~/.config/okularpartrc
~/.config/okularrc
~/.local/share/kxmlgui5/okular/part.rc
~/.local/share/kxmlgui5/okular/shell.rc

Nomenclature
Actions in the main toolbar:

Quick annotations
Actions in the annotation toolbar:

Annotation actions Highlighter, Underline, Squiggle, Strike out, Typewriter,
Inline note, Popup note, Freehand line, Arrow, Straight line, Rectangle, Ellipse,
Polygon, Stamp

Annotation config actions Line width, Color, Inner color, Opacity, Font, Annotation settings

Other actions Add to Quick Annotations, Pin

Autotests

 First run: annotation toolbar is not visible

 Selecting Tools > Annotations shows the annotation toolbar (below the main toolbar by default)

 Select an annotation > toolbar is shown

 Select a quick annotation > toolbar is shown

 Hide action (red cross) on the toolbar hides the toolbar

 Keys 1-9,0 select the (builtin) Annotation actions (one case tested)

 Keys Alt+1-9,0 select the quick annotation actions (one case tested)

 No annotation action selected: Quick Annotations is enabled, Add to quick annotations is disabled, Annotation config actions are disabled, Pin is enabled

 The current document is an image: Highlighter, Underline, Squiggle, Strike out are disabled (also in Quick annotations)

 The current document is protected: All actions are disabled

 Select annotation: the  Annotation config actions are enabled and their values set to the ones for the current annotation (taken from okularpartrc)

 Click an annotation action when none selected: browse mode is selected

 Click the currently selected annotation action: the action is unchecked and the tool disabled (back to browse mode)

 Click ESC: the currently selected annotation action is unchecked

 If Pin unchecked the selected annotation is unchecked after it has be used once and we are back to Browse mode

 The annotation systems works when multiple Okular tabs are open (the selected annotation is per-tab)

Manual tests

(TODO) Check that kconf_update updates the key AnnotationTools to QuickAnnotationTools in ~/.config/okularpartrc

Color icon is a format-text-color (if inline note or typewriter) or format-stroke-color for all other annotations
All actions have tooltips (some change based on the fact that the icon is enabled or not)
If a custom Line Width or Opacity is set through the Annotation Settings dialog, its value appears as a new checked action in the Line width or Opacity menu
If a custom stamp is selected through the Annotation Settings dialog, its name or filename (without path) appears as a new checked action in the Stamp menu
In Configure Okular > Annotations it is only possible to configure the quick annotations. Modifying them here updates the Quick annotations list after clicking Apply

The current document is an image: Highlighter, Underline, Squiggle, Strike out are disabled in Quick annotations
The state of Pin action is remembered across Okular launches
Selecting a quick action selects the corresponding action and loads its config values (color, line width, ...)
Setting the color and fill color works for all annotations (to be tested carefully, can be problematic for typewriter and inline note given the different internal mechanism to store the color in the settings)
Test stamp annotation (handled differently from the rest of the annotations)

Merge Request: graphics/okular!105