[ImgBot] Optimize images

*Total -- 1,084.76kb -> 1,027.24kb (5.3%)

/static/img/tutorials/ml/measures-central-tendency.jpg -- 98.56kb -> 88.76kb (9.95%)
/static/img/tutorials/ml/scatter-plots.jpg -- 103.14kb -> 94.09kb (8.78%)
/static/img/html-css-js.jpg -- 529.02kb -> 496.25kb (6.19%)
/docs/css/best-practices/smacss-architectural-layers-diagram.jpg -- 354.05kb -> 348.15kb (1.67%)

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

Author: ImgBotApp