Add a user permissions model

[bcipriano]

Is your feature request related to a problem? Please describe.
OpenCue does not currently provide a method for managing user permissions within a deployment. Any users with access to the deployment have full access to the deployment, including the ability to run jobs anywhere. For many users this is not acceptable -- they will need to selectively provide access to users at various levels -- facility, allocations, show, etc.

Describe the solution you'd like
Implement a system where:

• Each user can have a permission policy attached, granting or denying access to individual resources.
• Admins can set up a default policy for new users.

Describe alternatives you've considered
None.

Additional context
Blocked by #218.

[to09]

Please guide how should I start with this issue?

[bcipriano]

@to09 I'd strongly recommend avoiding this one for now :)

It's a massive amount of work requiring detailed design discussions from the TSC and likely months of coding work. Before this could even begin we would first need to add support for proper user accounts (#218), which by itself is a huge amount of work.

[to09]

sure