[ImgBot] Optimize images

*Total -- 2,574.37kb -> 2,452.49kb (4.73%)

/docs/images/logo.png -- 153.17kb -> 106.18kb (30.68%)
/docs/images/logo-wide.png -- 121.49kb -> 94.39kb (22.31%)
/docs/images/screen.png -- 221.73kb -> 185.18kb (16.48%)
/docs/images/bg-2.jpg -- 87.17kb -> 76.20kb (12.59%)
/docs/images/safari-pinned-tab.svg -- 3.00kb -> 2.88kb (3.91%)
/CONTRIBUTORS.svg -- 1,987.81kb -> 1,987.66kb (0.01%)

Signed-off-by: ImgBotApp <[email protected]>

Author: ImgBotApp