docs: update rbd mirror docs for block pool config

Remove legacy documentation for configuring RBD mirroring. While we
still support legacy mirroring configs, we want to encourage new users
to use the CephBlockPool configuration for mirroring.

Signed-off-by: Blaine Gardner <blaine.gardner@redhat.com>

Documentation/ceph-rbd-mirror-crd.md

@@ -49,53 +49,5 @@ If any setting is unspecified, a suitable default will be used automatically.
 
 ### Configuring mirroring peers
 
-On an external site you want to mirror with, you need to create a bootstrap peer token.
-The token will be used by one site to **pull** images from the other site.
-The following assumes the name of the pool is "test" and the site name "europe" (just like the region), so we will be pulling images from this site:
-
-```console
-external-cluster-console # rbd mirror pool peer bootstrap create test --site-name europe
-```
-
-For more details, refer to the official rbd mirror documentation on [how to create a bootstrap peer](https://docs.ceph.com/docs/master/rbd/rbd-mirroring/#bootstrap-peers).
-
-When the peer token is available, you need to create a Kubernetes Secret.
-Our `europe-cluster-peer-pool-test-1` will have to be created manually, like so:
-
-```console
-$ kubectl -n rook-ceph create secret generic "europe-cluster-peer-pool-test-1" \
---from-literal=token=eyJmc2lkIjoiYzZiMDg3ZjItNzgyOS00ZGJiLWJjZmMtNTNkYzM0ZTBiMzVkIiwiY2xpZW50X2lkIjoicmJkLW1pcnJvci1wZWVyIiwia2V5IjoiQVFBV1lsWmZVQ1Q2RGhBQVBtVnAwbGtubDA5YVZWS3lyRVV1NEE9PSIsIm1vbl9ob3N0IjoiW3YyOjE5Mi4xNjguMTExLjEwOjMzMDAsdjE6MTkyLjE2OC4xMTEuMTA6Njc4OV0sW3YyOjE5Mi4xNjguMTExLjEyOjMzMDAsdjE6MTkyLjE2OC4xMTEuMTI6Njc4OV0sW3YyOjE5Mi4xNjguMTExLjExOjMzMDAsdjE6MTkyLjE2OC4xMTEuMTE6Njc4OV0ifQ== \
---from-literal=pool=test
-```
-
-Rook will read both `token` and `pool` keys of the Data content of the Secret.
-Rook also accepts the `destination` key, which specifies the mirroring direction.
-It defaults to rx-tx for bidirectional mirroring, but can also be set to rx-only for unidirectional mirroring.
-
-You can now inject the rbdmirror CR:
-
-```yaml
-apiVersion: ceph.rook.io/v1
-kind: CephRBDMirror
-metadata:
-  name: my-rbd-mirror
-  namespace: rook-ceph
-spec:
-  count: 1
-  peers:
-    secretNames:
-      - "europe-cluster-peer-pool-test-1"
-```
-
-You can add more pools, for this just repeat the above and change the "pool" value of the Kubernetes Secret.
-So the list might eventually look like:
-
-```yaml
-  peers:
-    secretNames:
-      - "europe-cluster-peer-pool-test-1"
-      - "europe-cluster-peer-pool-test-2"
-      - "europe-cluster-peer-pool-test-3"
-```
-
-Along with three Kubernetes Secret.
+Configure mirroring peers individually for each CephBlockPool. Refer to the
+[CephBlockPool documentation](ceph-pool-crd.md#mirroring) for more detail.