feat: vertical slice application -> provider -> binding (#4)

Co-authored-by: Timo Behrendt <t.behrendt@t00n.de>
Co-committed-by: Timo Behrendt <t.behrendt@t00n.de>

README.md

@@ -11,6 +11,8 @@ Manual changes to the resources in Authentik will be overwritten by the operator
 | Custom Resource | CRD File                                                   | Short Name |
 | --------------- | ---------------------------------------------------------- | ---------- |
 | ProxyProvider   | [`proxyProvider.yaml`](`artifacts/crd/proxyProvider.yaml`) | pp         |
+| Application     | [`application.yaml`](`artifacts/crd/application.yaml`)     | app        |
+| PolicyBinding   | [`policyBinding.yaml`](`artifacts/crd/policyBinding.yaml`) | pb         |
 
 ### ProxyProvider
 
@@ -32,9 +34,49 @@ spec:
   invalidation_flow: 7acac1ef-19e3-4a6f-8d8d-14ca7031d184
   # The external host of your application.
   external_host: https://example.t00n.de
+  # The ID of the outpost, which at current point in time can only be retrieved from Authentik directly. In this example: "Proxy-Forward-Auth-Auto"
+  outpost: e004ffe7-4af6-4ac1-9e9d-522354799e1f
 ```
 
-The ProxyProvider will be created in Authentik, but will not be assigned to an outpost or an application (Resources are TBD).
+The ProxyProvider will be created in Authentik and assigned to the configured outpost.
+
+### Application
+
+The Application only supports a reduced set of fields.
+
+Example [`application.yaml`](`artifacts/examples/application.yaml`):
+
+```yaml
+apiVersion: application.t000-n.de/v1alpha1
+kind: Application
+metadata:
+  name: application-example
+spec:
+  name: Application Example
+  slug: application-example
+  # The ID of the provider, which can be retrieved from e.g. the ProxyPRovider via "kubectl get pp proxy-provider-example -o jsonpath='{.status.pk}'"
+  provider: 105
+```
+
+### PolicyBinding
+
+The PolicyBinding is used to bind a policy to a target, e.g. allow a group or user to access an application.
+The PolicyBinding only supports a reduced set of fields.
+
+Example [`policyBinding.yaml`](`artifacts/examples/policyBinding.yaml`):
+
+```yaml
+apiVersion: policybinding.t000-n.de/v1alpha1
+kind: PolicyBinding
+metadata:
+  name: policy-binding-example
+spec:
+  group: 14ab813f-a7f9-481b-9b08-781953ae9ebf
+  # The ID of the target, e.g. an Application, which can be retrieved from e.g. the Application via "kubectl get app application-example -o jsonpath='{.status.pk}'"
+  target: 8dd85627-9c48-49c2-8afc-d73dd122ffc2
+  # The order in which the policy is applied. This needs to be unique for each PolicyBinding.
+  order: 1
+```
 
 ## Versioning