Make “Allow repos to install/uninstall apps” a per-repo option

F-Droid support repos pushing install/uninstall requests automatically, and I intend to use it from my own F-Droid repo. However, I only want to allow those requests from my own repo, and no other.

At the moment, it seems this option is for all repos, or none. It seems like it would make more sense from a security perspective to be able to turn control it per repo, rather than (only) globally.