client: refactored and improved splitscreen for diagrams To make different diagrams possible, the splitscreen view needed to be decoupled from the cross profiles. Also the style has changed to make it more consistent with the rest of the app. The standard box header is now used and there are collapse and expand animations.

The gemma database schema requires PostgreSQL >= 11.

`dot.tmpl` is a template file for `postgresql_autodoc`
to be more similiar to UML and leave out some less useful labels.

See  `../docker/README.md`