Make a single endpoint for services

[dragazo]

Right now we have to hit potentially multiple services servers every time we do an RPC. It'd be better if we just had to do one request, and it could be a single point to add load balancing or smarter routing that avoids having to hit multiple servers (which are even worse potentially based on username and groups, etc.). Without this, scalability is basically a non-starter since every registered server receives every request.