900 context path

[longshuicy]

Update:
Everything should work now. For testing please refer to below section.

---

Test development:

1. export BASE_URL_ROUTE={your subdirectory}
2. npm run start:dev
3. go to http://localhost:3000/{your subdirectory}/. Any navigation between links should automatically goes to /subdirectory
4. unset BASE_URL_ROUTE && npm run start:dev. Everything should still run under root normally.
   Note: when logging in, the redirect_uri need to be configured in keycloak to reflect that subdirectory

Test production:

Please follow the instruction documentation. This includes several steps: e.g. Build frontend image; Run specific docker compose with context path; Configure keycloak

Make sure to test backward compatibility as well:

1. docker compose up
2. Everything should still run under root normally.

[longshuicy]

@max-zilla I recall you made some progress deploying under a subroute.
If possible, could you share your branch/ example where you've been experimenting with?