Chore: Provide basic documentation for KubeETL

[Blokje5]

We now cover the following in the README (no separate documentation site yet):

• What is KubeETL
• What concepts are there
• Some basic (working) examples
• Where do we want to go
• How to contribute

FYI to run the examples: Create a Kind Cluster Build the docker image of KubeETL Load the docker image kind load docker-image ghcr.io/dataworkz-nl:main Follow the installation guide (both argo workflows and kubeetl) Follow the examples.

I tried to run them and encountered some issues in the Dataset Controller (a panic somewhere). I will create a separate issue for it.

Closes #16

[Blokje5]

@ThijsKoot if you also have time for this PR that would be perfect!