Read and write .horde.yml files and changelog.yml files.
https://wiki.horde.org/Doc/Dev/HordeYmlFormat
Same or similar implementations existed in
- horde/horde-installer-plugin Composer plugin
- horde/components Developer CLI
- horde/hordectl Admin CLI
Depending on these packages for further use cases was not practical so I split off and generalized as far as I could.