client:pdf-gen:imporve some template elements * add property to define the border color of the elements * fix rounding of boxes to handle case that box is not rounded * check text for small version of date

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`