feat: add Centrifugo notification service with usage examples and tests

[srikary12]

Description

Adds Centrifugo notification service

Motivation and Context

Adds support to notify centrifugo service https://github.com/nikoksr/notify/issues/944

How Has This Been Tested?

make test
make fmt
make lint

Modifies webpush to pass test case <Need to cross check>

Screenshots / Output (if appropriate):

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Documentation (no code change)
• [ ] Refactor (refactoring production code)
• [x] Fixes webpush test case

Checklist:

• [x] My code follows the code style of this project.
• [x] I have updated the documentation accordingly.
• [x] I have added tests to cover my changes.
• [ ] All new and existing tests passed.

[srikary12]

The runner is receiving shutdown signal for lint. Am I missing something here?