[ImgBot] Optimize images

*Total -- 125.28kb -> 62.10kb (50.43%)

/assets/logo.png -- 46.55kb -> 20.55kb (55.86%)
/assets/logo-w.png -- 42.62kb -> 20.46kb (51.99%)
/assets/icon.png -- 26.39kb -> 14.62kb (44.62%)
/assets/adaptive-icon.png -- 9.72kb -> 6.47kb (33.38%)

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

Author: ImgBotApp