Remove the encyclopedia GUI and replace with links to old version in v1.0.0

We don't have an encyclopedia API for v1. Therefore, having the GUI does not make sense anymore.

• This is a cleanup, the following might not cover everything
• The only remaining encyclopedia things in v1.0.0, should be links directed towards http://nomad-lab.eu/prod/rae/encyclopedia (e.g. the current production of v0_8, this url should be configurable).
• There is bits of outdated encyclopedia config (also helm), env.js, flask serves GUI file, the submodule, stuff in Dockerfile, etc. that should be removed

@himanel1 Can you do this. It is not super urgent, but should be done somewhere the next couple of weeks.