Combine sessions/refresh and users/current calls

[alxndrsn]

Observed

HTTP1

HTTP2

Server-side

Both requests performed in series complete in ~100ms.

Expected

Could knock about 400ms off page-load time?

[matthew-white]

I like this idea! The /v1/users/current endpoint is already kind of unique. We add a preferences property to the response, which we don't do for other user endpoints. I think we could add a session property or something to the response with the information from /v1/sessions/restore (the session createdAt and expiresAt). The two endpoints feel related, so it makes sense to me to combine them.

If this change could be made on the backend, I'd be happy to update the frontend.

[alxndrsn]

If this change could be made on the backend, I'd be happy to update the frontend.

I had a go at getodk/central-backend#1602 - would that be suitable?

[matthew-white]

Looks great, I'll try my hand at the Frontend!