Capacity Planning Placeholder API

We have extended the capacity planning functionality so all the related data can be accessed via the Forecast API. Furthermore, we have updated the skills API to support levels.
You can find the documentation here for further details:Main page:
https://github.com/Forecast-it/API

Most relevant subpages:
https://github.com/Forecast-it/API/blob/master/sections/placeholders.md
https://github.com/Forecast-it/API/blob/master/sections/placeholder_allocations.mdUpdates to skills:
https://github.com/Forecast-it/API/blob/master/sections/skill_levels.md
https://github.com/Forecast-it/API/blob/master/sections/person_skills.md