[ImgBot] Optimize images

*Total -- 99.09kb -> 59.31kb (40.15%)

/docs/img/page-dia.svg -- 7.05kb -> 3.74kb (46.97%)
/docs/img/action-groups-dia.svg -- 12.82kb -> 7.32kb (42.92%)
/docs/img/test-dia.svg -- 30.08kb -> 18.05kb (40%)
/docs/img/data-dia.svg -- 12.56kb -> 7.56kb (39.82%)
/docs/img/metadata-dia.svg -- 26.91kb -> 16.44kb (38.89%)
/docs/img/section-dia.svg -- 9.67kb -> 6.20kb (35.86%)

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

Author: ImgBotApp