Add multi-device support for BACnet gateway routing (#1279)

* Expanded Object_List to Object_List[MAX_NUM_DEVICES] array to support per-device objects for virtual remote devices
* Added multi-device iteration for COV handler, device timer, and intrinsic reporting
* Added apps/gateway2 demo application
* When MAX_NUM_DEVICES == 1, behavior is identical to the original implementation
* Conditional compilation with macros ensures no impact on non-gateway applications

---------

Signed-off-by: Hyeongjun Kim <hjun1.kim@samsung.com>
Co-authored-by: haemeok-kang <haemeok.kang@samsung.com>

Makefile

@@ -160,6 +160,14 @@ gateway:
 gateway-win32:
 	$(MAKE) BACNET_PORT=win32 -s -B -C apps gateway
 
+.PHONY: gateway2
+gateway2:
+	$(MAKE) -s -B -C apps $@
+
+.PHONY: gateway2-win32
+gateway2-win32:
+	$(MAKE) BACNET_PORT=win32 -s -B -C apps gateway2
+
 .PHONY: piface
 piface:
 	$(MAKE) CSTANDARD="-std=gnu11" LEGACY=true -s -C apps $@
@@ -543,6 +551,7 @@ clean: ports-clean
 	$(MAKE) -s -C apps/router-ipv6 clean
 	$(MAKE) -s -C apps/router-mstp clean
 	$(MAKE) -s -C apps/gateway clean
+	$(MAKE) -s -C apps/gateway2 clean
 	$(MAKE) -s -C apps/sc-hub clean
 	$(MAKE) -s -C apps/fuzz-afl clean
 	$(MAKE) -s -C apps/fuzz-libfuzzer clean