[Feature] Support base url on the web app

Describe the bug Immich server is deployed using default _docker-compose.yml_ on the private host (Windows10) at It is accessible via reverse proxy (Windows Server 2019, IIS 10) at public url [ Main page is loaded successfully, but is not working. The reason is that /_app/immutable/start-a8372751.js file relative path is wrong: and therefore error 404 occured. All other files _(css, js, json, favicon, etc)_ are loaded successfully by their correct relative addresses /photosImmich/...path... Task List • I have read thoroughly the README setup and installation instructions. • I have included my docker-compose file. • I have included my redacted .env file. • I have included information on my machine, and environment. To Reproduce Steps to reproduce the behavior: 1. In browser, open developers console, Network tab 2. Go to [ 3. See downloaded files and errors Expected behavior • All files are downloaded by its relative paths /photo…