[ImgBot] Optimize images

*Total -- 190.79kb -> 121.54kb (36.3%)

/images/favicon-16x16.png -- 15.64kb -> 1.36kb (91.33%)
/images/owner-favicon-32x32.png -- 22.97kb -> 2.41kb (89.5%)
/images/favicon-32x32.png -- 18.66kb -> 2.36kb (87.35%)
/images/qrcode_for_yanglbme.jpg -- 102.81kb -> 85.33kb (17%)
/images/doocs.png -- 30.71kb -> 30.08kb (2.04%)

Signed-off-by: ImgBotApp <ImgBotHelp@gmail.com>

Author: ImgBotApp