nRF52840: Migrate variants to new structure (#7396)

variants/nrf52840/rak2560/platformio.ini

@@ -0,0 +1,22 @@
+; Firmware for the WisMesh HUB RAK2560, including a onewire module to talk to the RAK 9154 solar battery.
+[env:rak2560]
+extends = nrf52840_base
+board = wiscore_rak4631
+board_check = true
+build_flags = ${nrf52840_base.build_flags}
+  -I variants/nrf52840/rak2560
+  -D RAK_4631
+  -DGPS_POWER_TOGGLE ; comment this line to disable triple press function on the user button to turn off gps entirely.
+  -DRADIOLIB_EXCLUDE_SX128X=1
+  -DRADIOLIB_EXCLUDE_SX127X=1
+  -DRADIOLIB_EXCLUDE_LR11X0=1
+  -DHAS_RAKPROT=1 ; Define if RAk OneWireSerial is used (disables GPS)
+build_src_filter = ${nrf52_base.build_src_filter} +<../variants/nrf52840/rak2560> +<mesh/api/> +<mqtt/>
+lib_deps = 
+  ${nrf52840_base.lib_deps}
+  ${networking_base.lib_deps}
+  melopero/Melopero RV3028@^1.1.0
+  https://github.com/beegee-tokyo/RAK-OneWireSerial/archive/0.0.2.zip
+debug_tool = jlink
+; If not set we will default to uploading over serial (first it forces bootloader entry by talking 1200bps to cdcacm)
+;upload_protocol = jlink