Rename build.sh to build-app.sh and check if build already exists

stack_orchestrator/data/config/uniswap-interface/build-app.sh

@@ -5,6 +5,12 @@ if [ -n "$CERC_SCRIPT_DEBUG" ]; then
   set -x
 fi
 
+# Check and exit if a deployment already exists (on restarts)
+if [ -f ./build ]; then
+  echo "build already exists, remove volume to rebuild"
+  exit 0
+fi
+
 yarn build
 
 # Create symlink to host built files with correct URL path