Geomap: improve `network layer` with network weathermap behavior

<!-- Please only use this template for submitting feature requests --> Geomap `network layer` even is `beta` stage is very useful. Using it as it is now, we can render network such as this [one](https://gfn-gp4l-rare.public.nmaas.eu/d/ddyhkt7b8aosga/gp4l-topology?orgId=1). (screenshot below)  For now, the mid-point is computed manually but this can be integrated into `network layer` behavior as it would be more complex if edges are curved. This problem become more complex in case of node having multi-connections between them. The following suggestions are aiming to provide feedback to `network layer` and propose some suggestions/feature improvements **AS OPTIONS** in order to improve `network layer` user experience usage. 1- When using `network layer`, it is useful to have metric from both directions and a mid-point: User can choose to display the arrows can be spawned from edge extremity to the mid-node point 2- Edges can be curved (or parallel) as it is shown below (picture take from this [link](https://software.es.net/react-network-diagrams/#/example/parallel)) 3- Some nodes can be grouped in a `parent node`. When clicked on a parent node this can lead to another diagram panel. (drill-down feature) **Why is this needed**: [1] would simplify drastically the number of edges between nodes. In big networks this make a huge difference as you divide the number of link by 2 and provide clarity. Without mid-point the real network displayed [here](https://gfn-gp4l-rare.public.nmaas.eu/d/ddyhkt7b8aosga/gp4l-topology?orgId=1) would be harder to read for an operator. This is a feature that is essentially used a lot in TELECOM network Environment. [2] Is essential when you have multiple link between nodes [3] Also improve drastically clarity. Sometimes, the network operator need to switch from geo-graphical representation to network node representation. It would be up to the user o…