Public repository, but allow only private forks (BB-14760)

Currently, having a public repository allows anyone to create public forks. The problem with this is that someone searching for a repository hosted on Bitbucket will also see all the forks and won't know which one is the master without intimate Bitbucket knowledge.

Instead, it would great if a public repository would allow the same forking control as a private repository has "Allow forks", "Allow only private forks", "No forks".

The way it is now, it has forced me to remove all source code from the repository and just upload packaged files without the ability for others to fork and submit changes. In other words, I can't use version control at all with this feature missing.