Add annotation api & Improve code coverage

[ohmrefresh]

Pull Request Template

Description

• Add annotation API
• Improve unit test (Folder.py) & Fix missing param method get_folder_permission
• Improve unit test (grafana_api.py)
• Improve unit test (search_api.py)
• Improve code coverage dashboard.py

Have you written tests?

• Yes
• No

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

[m0nhawk]

Thank you for the changes. Especially for Annotations support and unit tests! 👍