Changed post/comment submit keyboard shortcut to ctrl+enter from shift+enter

Fixes reopened #3897
Add participants preview con conversations
Merge branch 'reoponed_issue3897' of https://github.com/RoonyH/diaspora into RoonyH-reoponed_issue3897
Merge branch 'add_conv_participants_preview' of https://github.com/marpo60/diaspora into marpo60-add_conv_participants_preview
use tooltip plugin to display the name under the avatar

(temporary solution until the proposed solution from the
[pull request](https://github.com/diaspora/diaspora/pull/4149) is
implemented)
bump configurate
fix failing conversations cuke