[DOCS] Remove dead compatible.openmqttgateway.com links (#2205) (#2322)

The compatible.openmqttgateway.com site is offline (TLS connection reset),
leaving 38 dead links across the docs and README. Repoint BLE device lists
to the canonical Theengs Decoder devices page already used by the navbar,
point boards/devices/parts references to the corresponding docs pages, and
drop the affiliate-site mentions and 'Where to Buy' links that have no live
equivalent. Also fix a malformed markdown link in docs/use/ble.md.

docs/setitup/lora.md

@@ -1,6 +1,6 @@
 # LoRa gateway
 ## Compatible parts
 An ESP32 board with a LoRa module.
-Ideally a TTGO board with LoRa module included see [compatible parts list](https://compatible.openmqttgateway.com/index.php/parts)
+Ideally a TTGO board with LoRa module included.
 
 With this kind of board there is no hardware modification needed.