- 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).