Add list of available run & build options to the beginning of corresponding section in readme

[leonard-huebner]

What?

I propose to add a list of available run and build options at the beginning of the How to build and run the ELISA Cluster demo section of the readme.

The items could be listed in order of increasing complexity, eg.

• fetch & run precompiled image
• build using docker container
• manual build (w/ & w/o cache)

For each item, a link to the document detailing the approach could be provided.
For each item, a very short For whom? and For what? description could be added.

Why?

I personally do not read the full build instructions in their entirety before I start executing them, but instead read and execute them step by step. If one approaches the current run & build section in this manner, one will for example learn about the build via docker only after one has basically finished the more laborious manual build. An overview of the different ways to run and build the demo at the beginning could improve the onboarding experience.