Refactor Changes concept to be more generic and extensible

Right now we can only use ChangesClass to enter user/admin/dev changes. But it doesn't support adding dependency-related entries, backward-related entries, translation-related entries, etc.

Implementation idea:

• It would be nice if we could reuse Changes to register a dependency. More generally everything in a RN should be modeleed in a Release Change
• So one solution is to completely refactor ReleaseNotes.Code.ChangesClass and to introduce a top level ReleaseNotes.Code.EntryClass
  • The EntryClass is generic and represent any type of entries (change/news entry, dependency entry, compatibility entry, translation entry, etc) + a specific xclass for each type of entry
  • The EntryClass xclass should have the following xproperties:
    • product
    • version
    • type ("change/news", "dependency", etc)
  • The Changes/NewsClass should have the following xproperties:
    • Audience (user, admin, dev)
    • Category
    • Importance
    • Title
    • Summary
  • The DependencyClass should have the following xproperties:
    • Dependency name
    • Dependency version
    • Dependency link (example: URL to a JIRA issue, URL to the dependency web site, etc)
  • etc

+ have one LT for each entry type.
+ have a new custom report UI to generate reports for each entry type