Docker and backend changes to support prod-lite mode

[chriswilty]

Description

Enables running both API and UI through the Express server, in "production lite" mode.

From project root:

// Build UI, if not already built or if not up to date with latest changes:
npm run build

// Run UI and API together:
npm start

Resolves #867

Screenshots

Hosted on localhost:3000, and API reached on localhost:3000/api

Notes

• Express server hosts UI as well as API, for running a built / bundled app
• Running in development mode is unchanged: spin up API and UI separately
• An additional Dockerfile is also provided, for running UI and API in same container
• Original Dockerfile in backend directory remains, for running just the API in a container

Concerns

• VITE_BACKEND_URL in frontend/.env.example has changed, so you will need to update your frontend/.env to match!

Checklist

Have you done the following?

• Linked the relevant Issue
• Added tests
• Ensured the workflow steps are passing

[pmarsh-scottlogic]

All seems sensible enough (not that I can claim to fully understand it)! Ran things locally with no problem. Didn't test docker because I don't want to faff about installing. Approved, but there are a couple of comments.

[chriswilty]

I nearly had a clean sweep of check failures 😓

On it....

[pmarsh-scottlogic]

Good changes to the readme, I should add. Very clear

[chriswilty]

@pmarsh-scottlogic Ok, this one should be good for a final sweep.

[pmarsh-scottlogic]

looks good. Got 2 comments, both of which are not blocking me from approving

[pmarsh-scottlogic]

this file wants a new line at the end of it

[chriswilty]

How strange, it has a newline in my local copy and it doesn't come up as a change.

[pmarsh-scottlogic]

Suggested change

	fileURLToPath(new URL('../../../frontend/dist', importMetaUrl())),
	fileURLToPath(new URL('@src/frontend/dist', importMetaUrl())),

does this work?

[chriswilty]

Nope, because @src would be relative to backend, and we are needing the frontend build.