nRF52840: Migrate variants to new structure (#7396)

variants/nrf52840/meshlink/platformio.ini

@@ -0,0 +1,31 @@
+; MeshLink board developed by LoraItalia. NRF52840, eByte E22900M22S (Will also come with other frequencies), 25w MPPT solar charger (5v,12v,18v selectable), support for gps, buzzer, oled or e-ink display, 10 gpios, hardware watchdog
+; https://www.loraitalia.it
+; firmware for boards with or without oled display
+[env:meshlink]
+extends = nrf52840_base
+board = meshlink
+;board_check = true
+build_flags = ${nrf52840_base.build_flags}
+  -I variants/nrf52840/meshlink
+  -D MESHLINK
+  -D GPS_POWER_TOGGLE ; comment this line to disable triple press function on the user button to turn off gps entirely.
+  -D EINK_DISPLAY_MODEL=GxEPD2_213_B74
+  -D EINK_WIDTH=250
+  -D EINK_HEIGHT=122
+  -D USE_EINK_DYNAMICDISPLAY            ; Enable Dynamic EInk
+  -D EINK_LIMIT_FASTREFRESH=5           ; How many consecutive fast-refreshes are permitted
+  -D EINK_LIMIT_RATE_BACKGROUND_SEC=30  ; Minimum interval between BACKGROUND updates
+  -D EINK_LIMIT_RATE_RESPONSIVE_SEC=1   ; Minimum interval between RESPONSIVE updates
+  -D EINK_LIMIT_GHOSTING_PX=2000        ; (Optional) How much image ghosting is tolerated
+  -D EINK_BACKGROUND_USES_FAST         ; (Optional) Use FAST refresh for both BACKGROUND and RESPONSIVE, until a limit is reached.
+  -D EINK_HASQUIRK_VICIOUSFASTREFRESH   ; Identify that pixels drawn by fast-refresh are harder to clear
+
+
+build_src_filter = ${nrf52_base.build_src_filter} +<../variants/nrf52840/meshlink>
+lib_deps = 
+  ${nrf52840_base.lib_deps}
+  https://github.com/meshtastic/GxEPD2/archive/55f618961db45a23eff0233546430f1e5a80f63a.zip
+debug_tool = jlink
+; If not set we will default to uploading over serial (first it forces bootloader entry by talking 1200bps to cdcacm)
+; Note: as of 6/2013 the serial/bootloader based programming takes approximately 30 seconds
+;upload_protocol = jlink