Add Trident SKR V1.3 in SPI mode; This PR will not work properly without PR#234

[GadgetAngel]

Add Trident SKR V1.3 in SPI mode, This PR will not work properly without PR #234 . It contains a link to the information in PR #234

In Community/Electronics/ added the following:

GadgetAngel folder images subfolder

updated Index.md file to add "Trident - BTT SKR V1.3 Wiring for both SPI and UART modes" (tri_skr_v13.md) tri_skr_v13.md is a parent to tri_skr_v13_spi_wiring.md.

reused two additional files: a. skrv13_Resources.md b. skrv13_RaspberryPi.md

added initial Removal of Jumpers diagram added initial preparation - Set Jumpers diagram for SKR V1.3 in SPI mode updated description for Trident wiring diagram in SKR V1.3 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: MCU XYE with heat sinks in SPI mode MCU Z with heat sinks in SPI mode added URL to the Klipper Configuration from VoronDesign/Trident GitHub Repo for SKR V1.3 board added links to other resources