Remove the concept of "trusted" RPC channel

Conceived as a temporary access control measure, this is no longer needed now that we have proper authentication and RPC ACL.

PUBLISHED_FROM=0631244c79c289dbb168ee7537388828a8c55348

mos.yml

@@ -11,7 +11,6 @@ config_schema:
   - ["rpc.mqtt", "o", {title: "RPC over MQTT settings"}]
   - ["rpc.mqtt.enable", "b", true, {title: "Enable RPC over MQTT"}]
   - ["rpc.mqtt.topic", "s", "", {title: "Topic to use for RPC requests and responses. The default is ${device.id}/rpc"}]
-  - ["rpc.mqtt.is_trusted", "b", true, {title: "Whether this channel can be used for privileged commands, such as changing configuration"}]
 libs:
   - origin: https://github.com/mongoose-os-libs/mqtt
   - origin: https://github.com/mongoose-os-libs/rpc-common

src/mgos_rpc_channel_mqtt.c

@@ -178,7 +178,7 @@ bool mgos_rpc_mqtt_init(void) {
         mg_rpc_channel_mqtt(mg_mk_str(mgos_sys_config_get_device_id()));
     if (mch == NULL) return MGOS_INIT_MG_RPC_FAILED;
     mg_rpc_add_channel(mgos_rpc_get_global(), mg_mk_str(MG_RPC_DST_DEFAULT),
-                       mch, mgos_sys_config_get_rpc_mqtt_is_trusted());
+                       mch);
   }
   return true;
 }