[Feature] System Editor

### Description
The GUI allows for editing full systems, as seen in the 'UniverisyExample' system in the `EcdarUniversity` example project. However, this feature has been neglected for a while and is not supported by the engines. Whether system editing should be updated or removed is to be decided.

So is the feature desired and how should it be used in the queries?
One suggestion is to simply reference it in the queries by name, like a component, following the syntax in Ecdar/Ecdar-Common#2.

### Reason For Request
The idea of the feature is to abstract multiple components into a system in a graphical way, to avoid specifying long, complicated queries in the query pane. It would allow the user to get a visual representation of the systems being queried.