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
add temporary image
add sweet GIF for VE Labs entry
update VE release date in WikiFeatures
Merge branch 'VideoSprint37' into VideoSprint34-DebugInfo