app: main: add main function

Add a main thread with zbus subscriber instead of callback.

Signed-off-by: Giacomo Dematteis <giacomo.dematteis@nordicsemi.no>

Author: DematteisGiacomo

app/src/Kconfig.main

@@ -25,6 +25,26 @@ config APP_REQUEST_NETWORK_QUALITY
 	help
 	  Request network quality on triggers.
 
+config APP_WATCHDOG_TIMEOUT_SECONDS
+	int "Watchdog timeout"
+	default 180
+	help
+	  Timeout in seconds for the main module watchdog.
+	  The timeout given in this option covers both:
+	    * Waiting for an incoming message in zbus_sub_wait_msg().
+	    * Time spent processing the message, defined by
+	      CONFIG_APP_MSG_PROCESSING_TIMEOUT_SECONDS.
+	  Ensure that this value exceeds CONFIG_APP_MSG_PROCESSING_TIMEOUT_SECONDS.
+	  A small difference between the two can mean more frequent watchdog feeds, which increases
+	  power consumption.
+
+config APP_MSG_PROCESSING_TIMEOUT_SECONDS
+	int "Maximum message processing time"
+	default 120
+	help
+	  Maximum time allowed for processing a single message in the module's state machine.
+	  The value must be smaller than CONFIG_APP_WATCHDOG_TIMEOUT_SECONDS.
+
 module = APP
 module-str = APP
 source "subsys/logging/Kconfig.template.log_config"