Notification message: support Trigger requirements

[chicco785]

Description

We are going to use notification message to notify real time about triggers.

Changes Made

• Support for device identifier
• Document message headers

Related Issues

Fixes #5

Checklist

• [x] I have used a PR title that is descriptive enough for a release note.
• [x] I have tested these changes locally.
• [ ] I have added appropriate tests or updated existing tests.
• [ ] I have tested these changes on a dedicated VM or a customer VM [name of the VM]
• [x] I have added appropriate documentation or updated existing documentation.

[barecheck[bot]]

Barecheck - Code coverage report

Total: 31.52% Your code coverage diff: NaN% ▴

Uncovered files and lines

File	Lines
pkg/task/v1/task.pb.go	56-60, 62-64, 66-68, 70-72, 79-81, 111-115, 117-119, 121-123, 125-127, 134-136, 159-161, 163, 174, 178-180, 182-186, 189-193, 196-200, 203-207, 210-214, 240-242, 244, 255, 259-261, 263-267, 270-274, 277-281, 284-288, 291-295, 298-302, 305-309, 381-385, 409-410, 412-421, 424-433