[ImgBot] Optimize images (#50)

* [ImgBot] Optimize images

*Total -- 835.49kb -> 774.47kb (7.3%)

/docs/examples/model-server/preview-qna.png -- 141.51kb -> 80.50kb (43.11%)
/docs/assets/images/output_8_0.svg -- 78.81kb -> 78.81kb (0%)
/docs/assets/images/output_9_0.svg -- 78.81kb -> 78.81kb (0%)
/docs/assets/images/output_6_0.svg -- 78.89kb -> 78.89kb (0%)
/docs/assets/images/output_5_0.svg -- 78.89kb -> 78.89kb (0%)
/docs/assets/images/output_4_1.svg -- 189.28kb -> 189.28kb (0%)
/docs/assets/images/output_5_1.svg -- 189.28kb -> 189.28kb (0%)

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

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Co-authored-by: ImgBotApp <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>