clusterctl support (#53)

* add provider manifests and docs

* Update local-providers docs

---------

Co-authored-by: Ludwig Bedacht <ludwig.bedacht@ionos.com>
Co-authored-by: lubedacht <132355999+lubedacht@users.noreply.github.com>

Author: mcbenjemaa

clusterctl-settings.json

@@ -0,0 +1,7 @@
+{
+  "name": "infrastructure-proxmox",
+  "config": {
+    "componentsFile": "infrastructure-components.yaml",
+    "nextVersion": "v0.1.0"
+  }
+}

docs/Local-Providers.md

@@ -0,0 +1,85 @@
+## How To Create Local Repositories for Cluster-API providers to user with clusterctl
+
+### Why?
+
+You might want to use `clusterctl init` to install your provider. If you are in your development phase, you cannot yet make use of that
+as `clusterctl` will either try to find providers, which are hardcoded in the CLI source code, you will have to specify some kind of configuration file
+that will point to the urls, where your providers are located. By convention, there must a `*-components.yaml` file, which is publicly available (e.g. Github releases).
+
+There are a few naming and versioning conventions that need to be fulfilled in order to let clusterctl generate the correct manifests.
+
+The following section will explain, how create a configuration file, which will allow you to setup the proxmox cluster-api provider on a kubernetes cluster
+using `clusterctl init`
+
+### Guide
+
+in order for clusterctl to make use of local providers, we need some kind of contract files, which have to be available.
+`metadata.yaml` and `*-components.yaml`
+
+the `*-components.yaml` file depends on the type of provider. For example `infrastructure-components.yaml, core-components.yaml`. 
+
+As an example of creating local repositories for cluster-api, kubeadm and proxmox, we first have to add a `clusterctl-settings.json` to our `proxmox` repository:
+
+```json
+{
+  "name": "infrastructure-proxmox",
+  "config": {
+    "componentsFile": "infrastructure-components.yaml",
+    "nextVersion": "v0.1.0"
+  }
+}
+```
+
+The labeling has to start with  `infrastructure-` as the clusterctl script expects precise labelling
+Then we also have to make sure, there is a `metadata.yaml` file in the root directory of the promox repository
+
+```yaml
+# metadata.yaml
+apiVersion: clusterctl.cluster.x-k8s.io/v1alpha3
+kind: Metadata
+releaseSeries:
+- major: 0
+  minor: 1
+  contract: v1beta1
+```
+
+Make sure that a `major` and `minor` version in the `metadata.yaml` matches the `nextVersion` in the `clusterctl-settings.json` file
+
+next we create another `clusterctl-settings.json` file in a locally checked out [cluster-api](https://github.com/kubernetes-sigs/cluster-api) repository.
+```json
+{
+  "providers": ["cluster-api", "infrastructure-proxmox", "bootstrap-kubeadm", "control-plane-kubeadm", "ipam-in-cluster"],
+  "provider_repos": ["../cluster-api-provider-proxmox", "../cluster-api-ipam-provider-in-cluster/"]
+}
+```
+
+The path to the different repositories must be from the root of the cluster-api repository.
+Make sure to clone [IPAM provider](https://github.com/kubernetes-sigs/cluster-api-ipam-provider-in-cluster) in same directory.
+
+Next we have to execute the helper script in the cluster-api repository to generate local providers
+
+```bash
+# go to the root directory of cluster api
+cd <cluster-api-repo-path>
+
+# run the helper script
+./cmd/clusterctl/hack/create-local-repository.py
+```
+
+next you can find the generated files in:
+
+`~/.config/cluster-api/dev-repository`
+
+The cli tool will also tell you how to invoke the command properly. Make sure that you use the correct config file
+
+Prior to executing `clusterctl init`, make sure to export the required environment variables:
+
+```
+# required
+export PROXMOX_URL=https://pve.example.com
+export PROXMOX_TOKEN="<TOKEN_ID>"
+export PROXMOX_SECRET="<TOKEN_SECRET>"
+
+# optional
+export CAPMOX_LOGLEVEL=4
+```

metadata.yaml

@@ -0,0 +1,6 @@
+apiVersion: clusterctl.cluster.x-k8s.io/v1alpha3
+kind: Metadata
+releaseSeries:
+- major: 0
+  minor: 1
+  contract: v1beta1