Use of multiple GitHub organizations is harmful

Arduino's repositories are now spread across at least four organizations:
- [arduino](https://github.com/arduino)
- [arduino-libraries](https://github.com/arduino-libraries)
- [bcmi-labs](https://github.com/bcmi-labs)
- [vidor-libraries](https://github.com/vidor-libraries)

GitHub has recently added the extremely useful feature of being able to [transfer issues between repositories](https://help.github.com/articles/transferring-an-issue-to-another-repository/). However, this is only allowed for repositories within an organization or owner.

I'm not sure of the feasibility of merging the existing organizations, but it would be a good idea to avoid creating any more in the future.

No source files, tests, or entry points are identified. Start by reviewing GitHub's issue-transfer documentation and the four linked organizations, then determine whether consolidation is feasible and what policy should govern future repositories. Done would require a maintainer decision and an agreed organizational plan, which this issue does not yet define.

Written by the indexing model from the issue text.