util.roles: Add a :policies() method to iterate through available policies
We don't expose the policies directly, to force people to go through :may().
However, there are times when we really just need to know what policies a
role has inside it (e.g. for reporting or debugging purposes).
For full information on our dependencies, version requirements, and
where to find them, see https://prosody.im/doc/depends
If you have luarocks available on your platform, install the following:
- luaexpat
- luasocket
- luafilesystem
- luasec