[ImgBot] Optimize images

*Total -- 601.04kb -> 281.44kb (53.18%)

/assets/images/icon.png -- 99.87kb -> 44.78kb (55.16%)
/assets/images/adaptive-icon.png -- 99.87kb -> 44.78kb (55.16%)
/assets/images/favicon.png -- 99.87kb -> 44.78kb (55.16%)
/assets/data/world-0.png -- 25.92kb -> 11.84kb (54.32%)
/assets/data/world-4.png -- 27.18kb -> 12.51kb (53.96%)
/assets/data/world-3.png -- 29.20kb -> 13.50kb (53.78%)
/assets/data/world-2.png -- 26.65kb -> 12.68kb (52.41%)
/assets/data/world-5.png -- 34.05kb -> 16.45kb (51.68%)
/assets/data/world-1.png -- 37.07kb -> 18.50kb (50.09%)
/assets/images/splash.png -- 121.37kb -> 61.61kb (49.24%)

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

Author: ImgBotApp