build(striker-ui): add default API URL in .env

striker-ui/.env

@@ -1,2 +1,2 @@
 # Use this to set a different origin
-NEXT_PUBLIC_API_URL=
+NEXT_PUBLIC_API_URL=/cgi-bin

striker-ui/Makefile.am

@@ -20,8 +20,6 @@ EXTRA_DIST		= $(nextoutdir)
 out:
 	-@echo "Install node modules (dependencies) prior to building."
 	npm install --no-package-lock --ignore-scripts
-	-@echo "Generate endpoint prefix."
-	sed 's@=.*@=/cgi-bin@' <env.development >.env.local
 	-@echo "Build front-end project."
 	npm run build
 	-@echo "Stage only the build output directory."