[ImgBot] Optimize images

*Total -- 448.60kb -> 315.72kb (29.62%)

/docs/images/architecture_diagram.png -- 71.90kb -> 28.46kb (60.42%)
/docs/images/program_configure.png -- 55.78kb -> 35.99kb (35.48%)
/docs/images/module.png -- 97.88kb -> 69.50kb (28.99%)
/docs/images/set_witness_param.jpeg -- 223.05kb -> 181.78kb (18.5%)

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

Author: ImgBotApp