Get rid of CSS transform on each annotation in the annotation layer

- each annotation has its coordinates/dimensions expressed in percentage,
  hence it's correctly positioned whatever the scale factor is;
- the font sizes are expressed in percentage too and the main font size
  is scaled thanks a css var (--scale-factor);
- the rotation is now applied on the div annotationLayer;
- this patch improve the rendering of some strings where the glyph spacing
  was not correct (it's a Firefox bug);
- it helps to simplify the code and it should slightly improve the update of
  page (on zoom or rotation).

web/annotation_layer_builder.js

@@ -117,11 +117,14 @@ class AnnotationLayerBuilder {
     if (this.div) {
       // If an annotationLayer already exists, refresh its children's
       // transformation matrices.
+      AnnotationLayer.setDimensions(this.div, viewport);
       AnnotationLayer.update(parameters);
     } else {
       // Create an annotation layer div and render the annotations
       // if there is at least one annotation.
       this.div = document.createElement("div");
+      AnnotationLayer.setDimensions(this.div, viewport);
+
       this.div.className = "annotationLayer";
       this.pageDiv.append(this.div);
       parameters.div = this.div;