[ImgBot] Optimize images

*Total -- 5,363.67kb -> 3,677.20kb (31.44%)

/_media/usage/file-dependency-diff.png -- 1,237.74kb -> 790.97kb (36.1%)
/_media/usage/file-diff.png -- 1,308.63kb -> 843.43kb (35.55%)
/_media/usage/another-diagram.png -- 1,144.78kb -> 807.15kb (29.49%)
/_media/usage/file_back.png -- 165.89kb -> 117.85kb (28.96%)
/_media/usage/interface-overview.png -- 1,263.37kb -> 911.38kb (27.86%)
/_media/usage/file_navigation.png -- 121.21kb -> 91.11kb (24.83%)
/_media/usage/diagram-navigation.png -- 50.29kb -> 45.18kb (10.15%)
/_media/usage/block-click.png -- 71.76kb -> 70.14kb (2.26%)

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

Author: ImgBotApp