ASA: Put tileserver URL in frontend config

**Describe the task**
Currently we hard code a single URL for the tileserver in the frontend, this should be put in the frontend configuration and point to the deployment instance it's a part of, e.g. prod for prod, pr-123 for pr-123

**Acceptance Criteria**
- [ ] Tileserv url is accessed through the frontend config on the frontend
- [ ] URL points to the deployment it's a part of

**Additional context**
- Add any other context about the task here.
- Or here

No files or tests are named; locate the frontend configuration entry point and the current hard-coded tileserver URL first. Confirm how deployment names such as prod and pr-123 are exposed, then verify the frontend reads the deployment-specific URL and that both acceptance criteria hold.

Written by the indexing model from the issue text.