use FE Dockerfile.dist

[milanmajchrak]

dist is significantly smaller, let's use it, if possible.

we must use preboot false in config to run dist image locally

can we do it now, or rather after first release? A lot would be changing!

[MajoBerger]

struggle: Vanilla DSpace build wrong postgres, so that needs fixing first, before assuring we can debug .dist, so that we can actually switch to it.

[MajoBerger]

@milanmajchrak this issue is about using Dockerfile.dist instead of Dockerfile for FE builds. It produces smaller images, therefore saves space. It uses multistage build, but the main advantage is only the smaller image. It could potentially break things, so we did not do this at the time. It can still be done later on.