[PLA-1659] Remove decoder from submodules

.gitmodules

@@ -1,6 +1,3 @@
 [submodule "wallet-daemon"]
 	path = wallet-daemon
-	url = https://github.com/enjin/wallet-daemon.git
-[submodule "platform-decoder"]
-	path = platform-decoder
-	url = https://github.com/enjin/platform-decoder.git
+	url = https://github.com/enjin/wallet-daemon.git

docker-compose.yml

@@ -28,8 +28,6 @@ services:
 
   decoder:
     image: enjin/decoder:latest
-    build:
-      context: ./platform-decoder
     restart: unless-stopped
     ports:
       - "${DECODER_EXTERNAL_PORT}:8090"