Widget stretch (#8969)

* Add new files and update .gitignore

* Horizontal and vertical stretch for form widgets

* Suggestions added

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Co-authored-by: Selma Vidimlic <selmaVH1>
(cherry picked from commit 3fa81f6)

docs/user_manual/working_with_vector/vector_properties.rst

@@ -2412,6 +2412,11 @@ this group helps you configure the look of the widget assigned to the field:
 * :guilabel:`Override label color`: applies specific color to the field's label
 * :guilabel:`Override label font`: applies specific font properties (bold, italic, underline,
   strikethrough, or font family) to the field's label
+* :guilabel:`Size`: allows to control how widgets will relatively resize when resizing an
+  attribute form.
+
+  * :guilabel:`Horizontal stretch`: sets a higher horizontal value for widgets that need more horizontal space.
+  * :guilabel:`Vertical stretch`: determines how widgets resize vertically when the form is resized.
 
 General options
 ^^^^^^^^^^^^^^^