Feat(service): Add Ntfy

[CybersShell]

Description

Motivation and Context

There was a feature request created in issue to add Ntfy service https://github.com/nikoksr/notify/issues/461

How Has This Been Tested?

I am currently testing against the default server, which I know is not best. I would like help mocking the endpoint.

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)
• [ ] Other

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.
• [x] All new and existing tests passed.