[docs] Steps for releasing Authorino Operator

RELEASE.md

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+# How to release Authorino Operator
+
+## Process
+
+To release a version “v0.W.Z” of Authorino Operator in GitHub and Quay.io, follow these steps:
+
+1. Pick a stable (released) version “v0.X.Y” of the operand known to be compatible with operator’s image for “v0.W.Z”;
+if needed, [make a release of the operand first](https://github.com/Kuadrant/authorino/blob/main/RELEASE.md).
+
+2. Run the GHA [Release operator](https://github.com/Kuadrant/authorino-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`
+   * Authorino version the operator enables installations of (without prefix) – i.e. `0.X.Y`
+   * If the release is a prerelease
+   * Bundle and catalog channels (comma-separated) – usually: `stable`
+
+3. Run the GHA [Build and push images](https://github.com/Kuadrant/authorino-operator/actions/workflows/build-images.yaml)
+for the “v0.W.Z” tag, specifying ‘Authorino version’ equals to “0.X.Y” (without the leading “v”). 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 `authorino-operator-v0.W.Z`
+
+2. Create a new directory _operators/authorino-operator/0.W.Z_ containing:
+
+   * Copy the bundle files from _github.com/kuadrant/authorino-operator/tree/v0.W.Z/bundle_
+   * Copy  _github.com/kuadrant/authorino-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.
+
+
+## Notes on Authorino Operator’s automated builds and references to the Authorino manifests and default version
+
+* PRs merged to the main branch of Authorino Operator cause a new image to be built (GH Action) and pushed automatically
+to _quay.io/kuadrant/authorino-operator:<git-ref>_ – the _quay.io/kuadrant/authorino-operator:latest_ tag is also moved
+to match the latest <git-ref>.
+
+* Authorino Operator owns the manifests required by the operator, i.e. Authorino CRD + role definitions, and hosts a copy
+of the operand’s manifests (CRD+roles), merged together with the deploy and bundle manifests:
+
+  * Stored in _config/deploy/manifests.yaml_ file that gathers resources of both operator (CRD, RBAC, Deployment, Service)
+  and operand (CRD, role definitions)
+    * Committing this file allows to install all the manifests and deploy an instance of the operator from a single
+    _kubectl apply_ command
+    * Tons of docs in the Authorino repo relying on that
+  * Make target manifests is used to generate the compiled version of all manifests (operator’s and operand’s).
+  It accepts as parameters:
+
+    * _VERSION_: sets the version of the manifests of the operator generated by the operator-sdk command and image tag of
+    the deployment added to _config/deploy/manifests.yaml_ (default: latest)
+    * _AUTHORINO_VERSION_: sets the operand’s branch that sources the manifests (CRD, role definitions) that are appended
+    to _config/deploy/manifests.yaml_ (default: latest)
+
+  * Changes in the operand’s CRD/role definitions out date the _config/deploy/manifests.yaml_ file, thus requiring a PR to
+  the operator repo ([example](https://github.com/Kuadrant/authorino-operator/pull/68))
+
+  * A make target _verify-manifests_ verifies consistency of the manifests
+    * Triggered in the CI tests
+    * Causes all PRs in the Operator repo to break whenever there’s a change in the operand’s API committed to the main
+    branch → requires immediate update of the copy of operand’s manifests in the main branch of the operator and rebase of all PRs
+
+  * Apart from the operand’s manifests pinned to a specific or latest version in the copy committed to
+  _config/deploy/manifests.yaml_, the Operator’s code contains hard-coded references to the default version of the operand
+  to install:
+    * See _v1beta1.DefaultAuthorinoImage_ (_api/v1beta1/authorino_types.go_)
+    * It can be overwritten in the Authorino CR → good for dev/test/staging workflows
+    * Set to `latest` in the main branch