Fix for #3345: Add Content-Type Header "application/json" to GET /version and /info responses in remote API

Docker-DCO-1.0-Signed-off-by: Manuel Woelker <github@manuel.woelker.org> (github: manuel-woelker)
Merge pull request #3402 from manuel-woelker/3345-add-content-type-header-to-version-remote-api

Fix for #3345: Add Content-Type Header "application/json" to GET /version response in remote API