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).

src/display/canvas.js

@@ -3021,9 +3021,6 @@ class CanvasGraphics {
           canvasHeight
         );
         const { canvas, context } = this.annotationCanvas;
-        const viewportScaleFactorStr = `var(--zoom-factor) * ${PixelsPerInch.PDF_TO_CSS_UNITS}`;
-        canvas.style.width = `calc(${width}px * ${viewportScaleFactorStr})`;
-        canvas.style.height = `calc(${height}px * ${viewportScaleFactorStr})`;
         this.annotationCanvasMap.set(id, canvas);
         this.annotationCanvas.savedCtx = this.ctx;
         this.ctx = context;