Integrated Alerting: Ability to copy (duplicate) alert rules

User Story: 

• As a PMM admin user, I need to be able to duplicate Alert Rule so it will be used for simplification of future editing 

UI:

 Acceptance Criteria: 

• The user is able to click the Duplicate button. 
• The new Alert rule created with the name "Copy of <alert rule name>" and in DISABLED status 
• As a User, when I trigger an action that successfully resolves, I can see a success notification.
• As a User, when I trigger an action that errors out, I can see an error notification.

Implementation details:

• code and PRs get pushed to percona-platform/grafana repository
• test coverage
• honor light/dark mode