Epic: Improve KaaS documentation

[jschoone]

For R7 we need better access to the docs of all the KaaS components.

Tasks:

• Add Cluster Stacks base docs #224
• Add Cluster Stack Operator #225
• Change CSPO docs to show the content instead of links to it #226
• Add Cluster Stack resource examples #227
• Add csctl #228
• Add cluster-gen #229
• Add Cluster Stacks with kamaji #230
• csctl Update docs for use in docs.scs.community csctl#149
• Cluster Gen Update docs for use in docs.scs.community cluster-gen#11
• Switch Cluster-Stacks and k8s-cluster-api-provider in https://docs.scs.community/docs/category/components-1
• Make the linter happy

[mbuechse]

Should this really be counted as closed? It seems that some tasks are still pending.