FE: Add `Cluster` filter to the `Operational vulnerabilities` vulnerability report

Why are we doing this work

• users want to see operational vulnerabilities and filter by the cluster they come from

Relevant links

• Design Issue
  • 

Non-functional requirements

• Documentation
• Testing:

Implementation plan

• frontend add cluster column to operational vulnerabilities tab
• frontend create a `cluster_filter.vue' in https://gitlab.com/gitlab-org/gitlab/blob/master/ee/app/assets/javascripts/security_dashboard/components/shared/filters/
• frontend conditionally render it on the Operational vulnerabilties tab