carta-frontend: Make the API endpoint configurable, or prepend the Base URL

[at88mph]

Describe the bug
We run the carta-backend and carta-frontend:

add-apt-repository ppa:cartavis-team/carta && \
apt update && \
apt install -y carta

In the browser, we serve it at some generated session ID:
https://example.com/sessions/carta/28938

Which works for most things, other than accessing the API endpoints (layout, database).

The apiAddress is looked up in the /config document:
https://github.com/CARTAvis/carta-frontend/blob/dev/src/index.tsx#L36

This is hard-coded to be an absolute path, if enabled (/api):
https://github.com/CARTAvis/carta-backend/blob/dev/src/HttpServer/HttpServer.cc#L111

Which means the current baseURL is ignored and the base /api is expected to be routed. Just making that api rather than /api would ensure it is kept in the current context, or simply making it configurable if it isn't already.

To Reproduce
Steps to reproduce the behaviour:
While running in the browser:

1. Go to 'View' -> 'Layouts' -> 'Save Layout'
2. Enter name
3. Click 'Save'
4. We expect https://example.com/sessions/carta/28938/api/database/layout, but the PUT is trying to use https://example.com/api/database/layout

Expected behaviour
Keep the API calls in the current context, under the current baseURL as declared in:
https://github.com/CARTAvis/carta-frontend/blob/dev/src/index.tsx#L32

Platform info (please complete the following information):

• MacOS Sonoma
• Browser Safari 17.2.1
• Browser Google Chrome 120.0.69

[at88mph]

Hi there. I noticed this got placed into GitHub Projects. Does that mean it will be looked into? Thanks!

[kswang1029]

We are handling this issue via CARTAvis/carta-backend#1338