Adjustments for power_to_H2-method

[lenzim97]

• Delete isolated O2-Buses, which are not considered in power-to-O2 links
• Filter out links PtO2 / PtHeat links, which are not connected to H2-buses
• buffer for h2 connection related to H2-Links: if a h2-link is within buffer range, connect nearest h2-bus of that link with ac-bus
• Implement Method of dynamic buffer to connect heat-buses
• Implement consideration of EHV-Buses: Execute whole method two times; first time for HVMV-Substation, second time for EHV-Substations ( use ehv-voronoi-cells as buffer for connecting WTTP)
• optional: increase bufferradius for h2 connection for EHV-Substation
• Implement different p_nom_max values for connection to HVMV or EHV-Subsattion: HVMV 120 MW, EHV Inf or 2GW-5GW
• Nice to Have: Consider optimization method for optimizing location of electrolyzer by adjusting the capital cost of the links