Users with 'monitoring-alertmanager-edit' role should access the observe tab in RHOCP4 web console

1. Proposed title of this feature request
Need non-administrator users to access the "observe" tab without having the cluster wide "cluster-monitoring-view" clusterrole assigned.

2. What is the nature and description of the request?
`cluster-monitoring-view` clusterrole assigns cluster wide access to the users for accessing the "observe" tab.
`monitoring-alertmanager-edit` role allows users to create and silence alerts in the Administrator perspective in the web console. 
Customers need a seperate role which will allow users to create and silence alerts as well as to access the "observe" tab without having the cluster-wide "cluster-monitoring-view" role.

3. Why does the customer need this? (List the business requirements here)
Customers want to use the least privileges possible. `monitoring-alertmanager-edit` role does not include 'observe' tab access.
`cluster-monitoring-view` gives a cluster wide access to the users, which is not required for few users.
Hence, customer is looking for a way to enhance the current role `monitoring-alertmanager-edit` with the permission to access the "observe" tab.

4. List any affected packages or components.