Leaflet map integration optimization for Layer control

[JonasPfeiffer123]

The interactive js based leaflet map replaced the static folium map a while ago. This brings much more functionality and faster data handling. It's currently possible to load the data as in the previous version, Layer colors can be changed. Data import & export basically works, even though export is not implemented in the data structure at this point.

It is possible to do so much more, from interacting with osm and LOD2 data to define the buildings for the project to creating new layers. Problem is the current structure of 4 layers for one net. This must be reduced to one file which requires changes in network generation and interaction with pandapipes.

This changes require further js imporvements as well as huge changes in data handling.