Improve Javadoc of the Annotations

[MaisiKoleni]

• Provide Javadoc for the elements of all the annotations (value and others).
• Update the information in the comments about security, hidden tests and deadlines.
• Promote most important and common annotations to stable API
• Document PathType a lot better including examples.
• Add more example in general about annotation usage
• Improve documentation of @Hidden and @Public