Widget type "Diagram"

As an API user I want to be able to attach widget of type Diagram and display its content on my dashboard.

Jira story: https://ufz-jira.scolution.de/browse/MWB-274

AC

• Widget type Diagram is implemented
• This widget type contains relation to specified DashboardDiagram and dataSeries property contains response from related DashboardDiagram
  • Some abstraction is required in order to specify dependant relations. In this case relation is DashboardDiagram, in some new Widget type it could be some other entity
    • Comment: there will be only this type of diagram that has related entities, so abstraction in this sense would be over-engineering. I implemented simple relation, which is required only for widget type 'Diagram'
• Values for this widget are calculated from the data subset to which the current user has permissions to see.
  • dataSeries JSON format: response from related DashboardDiagram
• Tests

Review

• Widget type Diagram is implemented
• This widget type contains relation to specified DashboardDiagram and dataSeries property contains response from related DashboardDiagram
  • Some abstraction is required in order to specify dependant relations. In this case relation is DashboardDiagram, in some new Widget type it could be some other entity
• Values for this widget are calculated from the data subset to which the current user has permissions to see.
  • dataSeries JSON format: response from related DashboardDiagram
• Tests