Move api url setting to docker build arg

docker/Dockerfile

@@ -1,10 +1,13 @@
 FROM node:19-alpine
 
+ARG api_url
+ENV LURE_WEB_API_URL $api_url
+
 RUN apk add git
 RUN git clone https://gitea.elara.ws/Elara6331/lure-web
 RUN cd lure-web && \
     npm i && \
-    LURE_WEB_API_URL='https://api.lure.elara.ws' npm run build
+    npm run build
 
 WORKDIR /lure-web
 ENTRYPOINT node build