feat: add t8s kaas offering

[cwrau]

No description provided.

[cwrau]

I hope I implemented this correctly, but at least my preliminary tests were successful.

[mbuechse]

Thanks @cwrau. At first glance, it looks promising! Will have to read carefully and write up a review, but due to vacation, it could take until July 22nd or so...

[mbuechse]

Question: you wrote that it's based on Gardener, yet you don't seem to use the Gardener API, but some Helm stuff (I still need to read more carefully). Is Gardener not exposed to your customers? If that's true, we should not mention Gardener.

[cwrau]

Question: you wrote that it's based on Gardener, yet you don't seem to use the Gardener API, but some Helm stuff (I still need to read more carefully). Is Gardener not exposed to your customers? If that's true, we should not mention Gardener.

Däh, where did you read that? 😅
I looked at git log -p again and I don't think I mentioned that anywhere, as it's not true anyways 😅