Minimal CI/CD for environment creation

[JoranAngevaare]

CI/CD for environment creation and testing

In this pull request, we add the minimal installation procedure for running E-OBS code.

• So far, we only install the dependencies without doing tests on the code or output.
• The installation and testing of the eobs code is envisaged for another PR. This will require some extra work since it requires access to the private repositories of ECA-D which we will need to setup first.

What does this PR add?

1. Scaffolding for CI/CD. Once we have created a (light weight) test for the eobs code, we can easily add that here (for example in the run_minimal_test.sh). The CI/CD is located in the .github/workflows folder.
2. A working set of versions that can be installed using miniforge , the required steps are added in the README.md.