Add useful information to the Sentinel status

[roivaz]

This PR adds the following information to the Sentinel status resource, so its more useful to monitor the status of the redis cluster:

• Shows the slave priority config option
• Shows some useful replication info

Example status:

❯ oc get sentinel stg-saas-sentinel -oyaml | yq -C ".status.monitoredShards[]"
name: shard01
servers:
  stg-saas-bck-storage01-04:
    address: 10.65.1.240:6379
    config:
      save: ""
      slave-priority: "100"
      slave-read-only: "yes"
    info:
      replication: 'master-link: up, sync-in-progress: no'
    role: slave
  stg-saas-bck-storage01-05:
    address: 10.65.6.181:6379
    config:
      save: ""
      slave-priority: "100"
      slave-read-only: "yes"
    info:
      replication: 'master-link: up, sync-in-progress: no'
    role: slave
  stg-saas-bck-storage01-06:
    address: 10.65.10.1:6379
    config:
      save: ""
      slave-priority: "100"
    role: master
name: shard02
servers:
  stg-saas-bck-storage02-01:
    address: 10.65.0.41:6379
    config:
      save: ""
      slave-priority: "100"
    role: master
  stg-saas-bck-storage02-02:
    address: 10.65.5.246:6379
    config:
      save: ""
      slave-priority: "100"
      slave-read-only: "yes"
    info:
      replication: 'master-link: up, sync-in-progress: no'
    role: slave
  stg-saas-bck-storage02-03:
    address: 10.65.10.167:6379
    config:
      save: ""
      slave-priority: "100"
      slave-read-only: "no"
    info:
      replication: 'master-link: up, sync-in-progress: no'
    role: slave

[roivaz]

/kind feature
/priority important-soon
/assign

[3scale-robot]

LGTM label has been added.

Git tree hash: 5ba48f469b6bbd4e4d394f232375fc0a9f3eaa5d

[roivaz]

/approve

[3scale-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: roivaz

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [roivaz]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[roivaz]

Related to https://github.com/3scale/platform/issues/868