FLomb/Calliope-Italy: v0.2 - Direct & Indirect Electrification options

v0.2 - Direct & Indirect Electrification options is an upgrade of the previous "Direct Electrification" model version, which now includes also power-to-gas options (electrolysers, methanation with direct air capture) and the possibility to use carbon-neutral gas in the existing infrastructure (gas network, gas network storage, gas turbines). This version has been used for the revised submission of the associated paper.