BAC-770: ImageServing

Don't return images that can not be rendered by thumbnailer (i.e. audio, video and SVG)
Iniitial checkin
Swift: enable on all Poznań devboxes, tej!
BAC-770: add unit test
Added additional debug info
update the base URL
Merge branch 'dev' into bac-770-image-serving-mime-blacklist
Revert "Swift: enable on all Poznań devboxes, tej!"

This reverts commit d80d596f7acca4f9b72ad7d823ca18c0683b35c1.
CE-419 Special:CloseWiki/information fix dumps urls
explain the meaning of the S3_MIGRATION constant
(DAR-2321) Make Chat module full width on main pages with grid
BAC-941: GlobalFile domains

GlobalFile is not using wikia.nocookie.net on production env
Specify the group for the Chat metrics.
(DAR-2753) Remove quote button on closed threads
Changing wfMsg -> wfMessage + whitespace cleanup
add VisualEditor title and description to WikiaLabs i18n
Merge branch 'dev' into ve-sprint-7
add temporary image
add sweet GIF for VE Labs entry
update VE release date in WikiFeatures