[docs] Adding release docs

Signed-off-by: dd di cesare <didi@posteo.net>

RELEASE.md

@@ -0,0 +1,51 @@
+# How to release Kuadrant Operator
+
+## Process
+
+To release a version _“v0.W.Z”_ of Kuadrant Operator in GitHub and Quay.io, follow these steps:
+
+1. Kuadrant dependencies need to be released first:
+   * [Authorino Operator](https://github.com/Kuadrant/authorino-operator/blob/main/RELEASE.md).
+   * [Limitador Operator](https://github.com/Kuadrant/limitador-operator/blob/main/RELEASE.md).
+   * [DNS Operator](https://github.com/Kuadrant/dns-operator/blob/main/docs/RELEASE.md).
+   * [WASM Shim](https://github.com/Kuadrant/wasm-shim/).
+
+2. Run the GHA [Release operator](https://github.com/Kuadrant/kuadrant-operator/actions/workflows/release.yaml); make
+   sure to fill all the fields:
+
+    * Branch containing the release workflow file – default: `main`
+    * Commit SHA or branch name of the operator to release – usually: `main`
+    * Operator version to release (without prefix) – i.e. `0.W.Z`
+    * Kuadrant dependencies (WASM Shim, Authorino, Limitador and DNS operators) versions (without prefix) – i.e. `0.X.Y`
+    * Operator replaced version (without prefix) – i.e. `0.P.Q`
+    * If the release is a prerelease
+
+3. Run the GHA [Build and push images](https://github.com/Kuadrant/kuadrant-operator/actions/workflows/build-images-base.yaml)
+   specifying ‘Kuadrant operator version’ and its dependencies equals to the previously released versions _“0.X.Y”_. This will cause the
+   new images (bundle and catalog included) to be built and pushed to the corresponding repos in
+   [quay.io/kuadrant](https://quay.io/organization/kuadrant).
+
+
+### Publishing the Operator in OpenShift Community Operators
+Open a PR in the [OpenShift Community Operators repo](http://github.com/redhat-openshift-ecosystem/community-operators-prod)
+([example](https://github.com/redhat-openshift-ecosystem/community-operators-prod/pull/1595) |
+[docs](https://redhat-openshift-ecosystem.github.io/community-operators-prod/operator-release-process/)).
+
+The usual steps are:
+
+1. Start a new branch named `kuadrant-operator-v0.W.Z`
+
+2. Create a new directory `operators/kuadrant-operator/0.W.Z` containing:
+
+    * Copy the bundle files from `github.com/kuadrant/kuadrant-operator/tree/v0.W.Z/bundle`
+    * Copy `github.com/kuadrant/kuadrant-operator/tree/v0.W.Z/bundle.Dockerfile` with the proper fix to the COPY commands
+      (i.e. remove /bundle from the paths)
+
+### Publishing the Operator in Kubernetes Community Operators (OperatorHub.io)
+
+1. Open a PR in the [Kubernetes Community Operators repo](https://github.com/k8s-operatorhub/community-operators)
+   ([example](https://github.com/k8s-operatorhub/community-operators/pull/1655) | [docs](https://operatorhub.io/contribute)).
+
+2. The usual steps are the same as for the
+   [OpenShift Community Operators](https://docs.google.com/document/d/1tLveyv8Zwe0wKyfUTWOlEnFeMB5aVGqIVDUjVYWax0U/edit#heading=h.b5tapxn4sbk5)
+   hub.