KKP User Cluster Management with Terrafrom Rest API and Cluster CRDs

[toschneck]

closes https://github.com/kubermatic/sig-cs-infra/issues/62

What this PR does / why we need it:

Shows the ability how KKP and Terraform could interact. The Provider is considered as example to extend it to the custom needs and cloud providers. As first example kubevirt is added

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

- Adding KKP REST API Terraform provider (Scope: Example Implementation to extend to custom needs)
- Adding Examples How to manage KKP User Cluster with Cluster CRDs at the seed level

[dharapvj]

May we should add few more things via kubectl :

1. Addon and AddonConfig CR
2. ApplicationInstallation CR
3. User-MLA Alerts (No CR I guess. Gets applied directly in Cortex?)
4. User-MLA AlertManager config (AlertManager CR)

I can try to add these after your PR is merged

[dharapvj]

/lgtm
/approve

[kubermatic-bot]

LGTM label has been added.

Git tree hash: 56cfc7228f21e54b529595d6d4f3cd4f4fe395ac

[kubermatic-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dharapvj

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [dharapvj]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[toschneck]

May we should add few more things via kubectl :

1. Addon and AddonConfig CR
2. ApplicationInstallation CR
3. User-MLA Alerts (No CR I guess. Gets applied directly in Cortex?)
4. User-MLA AlertManager config (AlertManager CR)

I can try to add these after your PR is merged

aggree created new issue for this #123

[toschneck]

fixed issues and add architecture overview.

[toschneck]

/lgtm

[kubermatic-bot]

@toschneck: you cannot LGTM your own PR.

In response to this:

/lgtm

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.