updated Electrical Index.md file to add the Switch-Wire SKR mini E3 V3.0.
added initial preparation diagram
added description for wiring diagram
added wiring diagram for Voron Switch-wire
added Color Pin diagram for Bigtreetech SKR mini E3 V3.0
added URL to the original Bigtreetech Github Repo on the SKR mini E3 V3.0 board
updated Electrical Index.md file to add the Switch-Wire SKR mini E3 V3.0. added initial preparation diagram added description for wiring diagram added wiring diagram for Voron Switch-wire added Color Pin diagram for Bigtreetech SKR mini E3 V3.0 added URL to the original Bigtreetech Github Repo on the SKR mini E3 V3.0 board