Add initial Personal Carbon Allowance Dataset

An initial prototype of this idea was produced during the Climate Emergency Strike on the 20th of September 2019.
The idea was to (in the first instance) capture individuals' limits on carbon consumption to aid decision making.
With these limits varying (and tampering down) yearly.

The key outstanding action here will be to document source and assumptions fully.
This is indeed non trivial as will vary based on regional and legislative assumptions so good fully documented `BH.oM.Data.Library.Source` is need

#### Todo:
- [ ] document source and clear reference and assumptions for the dataset