Simplify Network code

[veenstrajelmer]

Is your feature request related to a problem? Please describe.
The Mesh2d class was simplified in #574. The main improvement was to avoid the fact that manually set mesh2d_node_x and all other properties to by out of sync with the ones in meshkernel. All grid editing is now done directly in meshkernel and the mesh2d_node_x is now a class property that gets the node_x from meshkernel. In the other classes, the properties in the class and the properties in the meshkernel are still synced manully, with _process() functions and such. However, first wait on #575 to be fixed.

Describe the solution you'd like
This should also be done for Mesh1d and other classes. One issue is that Mesh1d has network and mesh1d properties, are both represented in meshkernel? We could also consider to deprecate Mesh2d, Mesh1D and other classes and do everything from the Network class. This would make sense since one only has one meshkernel instance for the 1d/2d/links meshes (now a separate meshkernel instance per thing). This would simplify the code drastically and only one meshkernel/network is used per network, makes sense. API changes are needed in that case.