[ImgBot] Optimize images

*Total -- 3,417.91kb -> 2,805.73kb (17.91%)

/images/tcie-3.x-input-for-db-dumps.png -- 17.95kb -> 6.82kb (62%)
/images/tcie-3.x-ssl-2.png -- 24.60kb -> 10.36kb (57.87%)
/images/tcie-3.x-default-build-env.png -- 15.51kb -> 6.74kb (56.51%)
/images/2019-07-settings-ssh-key.png -- 26.53kb -> 11.61kb (56.23%)
/images/2019-07-settings-env-vars.png -- 153.42kb -> 77.10kb (49.75%)
/images/tcie-3.x-setting-up-Port.png -- 493.46kb -> 303.42kb (38.51%)
/images/ui/icon-flag.svg -- 0.50kb -> 0.35kb (29.71%)
/images/tcie-3.x-input-for-encryption-key.png -- 15.02kb -> 10.67kb (28.99%)
/images/2019-04-15-xenial-build-log.png -- 26.64kb -> 19.07kb (28.42%)
/images/tcie-3.x-self-hosted-db.png -- 55.22kb -> 40.13kb (27.33%)
/images/ui/icon-arrowtabs.svg -- 0.56kb -> 0.41kb (26.49%)
/user/images/oss-migration/repos-to-migrate.png -- 38.22kb -> 28.42kb (25.66%)
/images/tcie-3.x-check-updates.png -- 25.24kb -> 18.98kb (24.8%)
/images/tcie-3.x-setting-up-OAuth.png -- 319.08kb -> 241.72kb (24.25%)
/images/error/404-hills-left.svg -- 1.18kb -> 0.90kb (23.76%)
/images/error/404-hills-right.svg -- 1.67kb -> 1.32kb (20.52%)
/images/ui/search.svg -- 1.31kb -> 1.05kb (19.99%)
/images/tcie-3.x-setting-up-Secret.png -- 302.23kb -> 242.14kb (19.88%)
/images/tcie-3.x-setting-up-License.png -- 81.37kb -> 67.13kb (17.49%)
/images/tcie-3.x-setting-up-Header.png -- 64.81kb -> 56.43kb (12.93%)
/images/tcie-3.x-ssl-1.png -- 49.96kb -> 43.54kb (12.86%)
/images/tcie-3.x-setting-up-RSA.png -- 475.39kb -> 415.06kb (12.69%)
/images/ui/travis-logo.svg -- 2.52kb -> 2.22kb (12.19%)
/images/ui/docs-desktop.svg -- 84.21kb -> 76.09kb (9.65%)
/images/tcie-3.x-list-of-versions.png -- 40.59kb -> 37.36kb (7.95%)
/images/ui/cones.svg -- 4.90kb -> 4.63kb (5.52%)
/slate/source/fonts/icomoon.svg -- 5.25kb -> 5.01kb (4.72%)
/images/error/pensive-travis.svg -- 30.79kb -> 29.44kb (4.4%)
/images/migrate/sign-up-for-the-beta-to-migrate.png -- 106.09kb -> 102.61kb (3.28%)
/images/error/excavator.svg -- 26.65kb -> 25.84kb (3.05%)
/images/ui/footer-logo.svg -- 49.62kb -> 48.58kb (2.11%)
/images/logo.svg -- 3.50kb -> 3.46kb (1.14%)
/images/hiro-animated.gif -- 497.66kb -> 492.89kb (0.96%)
/images/tcie-3.x-setting-up-Details.png -- 117.04kb -> 116.26kb (0.67%)
/images/tcie-3.x-setting-up-JSON.png -- 245.66kb -> 244.46kb (0.49%)
/images/tcie-3.x-setting-up-loadbalancer.svg -- 13.55kb -> 13.54kb (0.06%)

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