[ImgBot] Optimize images

*Total -- 1,607.77kb -> 807.05kb (49.8%)

/src/assets/screenshots/screenshot-4.png -- 156.64kb -> 61.83kb (60.53%)
/src/assets/screenshots/screenshot-3.png -- 468.42kb -> 220.59kb (52.91%)
/src/assets/screenshots/screenshot-1.png -- 226.57kb -> 109.68kb (51.59%)
/src/assets/screenshots/screenshot-5.png -- 414.06kb -> 201.84kb (51.25%)
/src/assets/screenshots/screenshot-2.png -- 245.62kb -> 120.50kb (50.94%)
/src/assets/login/header.png -- 8.39kb -> 5.62kb (33%)
/src/assets/intro/slide1.svg -- 54.00kb -> 53.29kb (1.31%)
/src/assets/intro/slide2.svg -- 32.92kb -> 32.54kb (1.18%)
/src/assets/shapes.svg -- 1.15kb -> 1.15kb (0.09%)

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

Author: ImgBotApp