samples: nrf9160: mmss: Simplify connection loop

Rewrite connection loop with simpler event structure

IRIS-5814

Signed-off-by: Georges Oates_Larsen <georges.larsen@nordicsemi.no>

samples/cellular/nrf_cloud_mqtt_multi_service/Kconfig

@@ -29,13 +29,6 @@ config CLOUD_CONNECTION_RETRY_TIMEOUT_SECONDS
  If connecting to nRF Cloud takes longer than this timeout, it will be
  reattempted.
 
-config CLOUD_CONNECTION_REESTABLISH_DELAY_SECONDS
- int "Cloud connection reestablishment delay (seconds)"
- default 5
- help
- After the connection to nRF Cloud has been reset, wait this amount of
- time before attempting to connect again.
-
 config CLOUD_READY_TIMEOUT_SECONDS
  int "Cloud readiness timeout (seconds)"
  default 600

samples/cellular/nrf_cloud_mqtt_multi_service/src/application.c

@@ -305,7 +305,7 @@ void main_application_thread_fn(void)
  }
 
  /* Wait for first connection before starting the application. */
- (void)await_connection(K_FOREVER);
+ (void)await_cloud_ready(K_FOREVER);
 
  (void)nrf_cloud_alert_send(ALERT_TYPE_DEVICE_NOW_ONLINE, 0, NULL);