Add Trident SKR 2 wiring diagram, This PR will not work properly without PR #271

[GadgetAngel]

*Add Trident SKR 2 wiring diagram, This PR will not work properly without PR #271 . It contains a link to the information in PR #271

*updated Electrical Index.md file to add the Trident SKR 2 (tri_skr2_uart_wiring.md)

*reused two additional files:
a. skr2_RaspberryPi.md
b. skr2_Resources.md

*added initial Removal of Jumpers diagram
*added initial preparation - Set Jumpers diagram for SKR 2
*updated description for wiring diagram in SKR 2
*added wiring diagram for Trident - SKR 2
*added the heatsink diagram to remind user to ensure that the heatsinks are installed on the stepper motor drivers for:

1. MCU XYE with heat sinks
2. MCU Z with heat sinks

*Klipper Configuration from VoronDesign/VoronUsers TechnoPhreak's GitHub Repo (https://raw.githubusercontent.com/VoronDesign/VoronUsers/master/firmware_configurations/klipper/TechnoPhreak/BTT_SKR_v2/printer.cfg) for SKR 2 board
*added SSR wiring diagram using SKR 2
*Updated Color Pin diagram for Bigtreetech SKR 2
*added original SKR 2 pinout
*added URL to the original Bigtreetech Github Repo on the SKR 2 board

[keyboard-magpie]

I want to revoke that review as I didn't spot the merge conflicts.

With GadgetAngel appearing to be absent for the last while, I'm not sure the big list of PRs from them would get updated, so we may need to close them all.