Super chapters

[benedeki]

Background

Better organization of chapters.
Some repositories contain more modules. It would be nice to organize the output by chapters.

Feature

Allow a definition of a similar map as for chapters (label to super chapter)that will define super chapters. The release note chapters will then be repeated in each super chapter.
NB!
Finding a label for super chapter doesn't stop further scan for other super chapter labels. Meaning a release note entry can be repeated in different super chapters.

Example

### Atum server
#### Enhancements
* some change X
* some change Y

### Atum agent
#### Enhancements
* some change X
#### Bugfixes
* fixed bug A