[ENHANCEMENT] Supporting multiple hosting/ service providers per user

[mrchrisadams]

Is your feature request related to a problem? Please describe.

In our system hosting providers only support having one user.

This is a problem for users who want to update more than one provider, or cases where we have one provider who might have multiple users who update it/

Describe the solution you'd like

Hosting providers can have multiple users allocated to them.

Users can be allocated to multiple hosting providers.

Additional context

I'm wincing as I write this, as I think the assumption of one user one provider maybe in a lot of places.