Use runtime env var for login page message to lower web container startup time (#577)

* Use runtime env var for loginPageMessage

* Rename VITE_LOGIN_PAGE_MESSAGE to PUBLIC_LOGIN_PAGE_MESSAGE in .env.example

* Move docker image `npm run build` step into Dockerfile

* Remove comment from web Dockerfile

web/Dockerfile

@@ -13,6 +13,8 @@ RUN npm ci
 
 COPY --chown=node:node . .
 
+RUN npm run build
+
 EXPOSE 3000
 
 FROM base AS dev
@@ -22,6 +24,3 @@ CMD ["npm", "run", "dev"]
 
 FROM base as prod
 ENV NODE_ENV=production
-
-
-# Issue build command in entrypoint.sh to capture user .env file instead of the builder .env file.