Add support to `type` field in the Changelog
In MR https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11579 we add the type field to unreleased changelog entries created with bin/changelog
.
This MR handles the type field in the creation of the CHANGELOG.md
and sort entries by type importance and entry ID ascending.
The order of type importance is the following:
1. Security fix
2. Feature removal
3. Bug fix
4. New deprecation
5. Feature change
6. New feature
7. Other