Add Trident SKR 2 in SPI mode; This PR will not work properly without PR #272

[GadgetAngel]

*Add Trident SKR 2 in SPI mode, This PR will not work properly without PR #272 . It contains a link to the information in PR #272

*In Community/Electronics/ added the following:

GadgetAngel folder images subfolder

*updated Index.md file to add "Trident - BTT SKR 2 Wiring for both SPI and UART modes" (tri_skr2_wiring.md) *tri_skr2_wiring.md is a parent to tri_skr2_spi_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 in SPI mode *updated description for Trident wiring diagram in SKR 2 in SPI mode *added the heatsink diagram to remind user to ensure that the heatsinks are installed on the stepper motor drivers for: *Added the following:

1. MCU XYE with heat sinks in SPI mode
2. MCU Z with heat sinks in SPI mode

*added URL to the 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 links to other resources