This adds GPS time synchronization for the following gateways:
RAK7267
RAK7289v2
If these gateways are operating as Relay gateways (ChirpStack Gateway Mesh) this assures that the heartbeat timestamp is accurate.
RAK7268v2 multi-slot
This changes the RAK7268v2 image to support multiple slots. While this gateway is (currently) sold with a single concentrator module, it is possible to install an additional concentrator module, for example a 2.4GHz module to use together with the ChirpStack Gateway Mesh feature. (#5)
Note: After upgrading, you must re-configure the Concentratord / MQTT Forwarder and Gateway Mesh (if used) to use the Slot 1 configuration.
Other improvements
Show all Gateway IDs in web-interface footer. (#7)
RAK7391: Add SPI device-paths to concentrator selector. (#6)
RAK7391: Add reset GPIOs for SPI concentrators. (#9)