Update slider styles

[gfellerph]

There is a way to style the left part of the track in every browser and the focus styles changed. Update the slider CSS component accordingly.

Design: https://www.figma.com/file/xZ0IW0MJO0vnFicmrHiKaY/Components-Post?type=design&node-id=16545%3A53351&mode=design&t=fYGLSZ9g8fLp5RDs-1

Tasks

Preview Give feedback

1. Update the styles for left track according to https://stackoverflow.com/questions/72837338/is-it-possible-to-style-input-type-range-with-just-a-left-and-right-color-and-no
2. Rename the "Range" page on the docs to "Slider"
3. Update focused styles
4. Design review

[imagoiq]

After discussion on #2781 in the Pattern discussion today, we'll go with option 4 and have the focus style on the whole group of input and label and use the css workaround with box-shadow.