Add all scs components to the docs and display them on the overview map

[maxwolfs]

For the architectural overview of the sovereign cloud stack we need all components that lie within the scs org with at least one individual markdown file in this repository.

You can see the current state on the staging branch: https://docs-staging.scs.community/docs

This being built from this branch/PR: #109

The graphic is being rendered from this json from the same branch.

It needs more content that already exists but is not visible.

To-do

Add docs of the following components/repositories (at least one markdown file within the docs)

• Container Registry (container layer)
• Monitoring (ops layer)
• Cluster stacks (container layer) @matofeder & @jschoone

Still to discuss is:

• If and how to add further upstream projects.
• Which labels are helpful? (Mandatory/Optional are categories of the standards, not the Ref.Impl.)