Add RBAC to support read-only users in an org

[asasas234]

Currently, all users that are invited into an org in Pixie are given admin-level permissions.
Admin users should have the ability to designate other admins, or invite new users with read-only permissions. This will prevent non-administrators from misconfiguring settings, adding other unwanted users, etc.

[MrAta]

+1, in an airgap deployment, it seems that by default the invited users are admin by default.

[aimichelle]

Hi all, Pixie currently does not have RBAC support. In all deployments of Pixie Cloud, all users who join the org will have admin privileges.

In the near future we would like to support both read-only and write-only permissions, along with finer-grained rules such as entity-level, table-level, and column-level RBAC.

@asasas234 , hopefully you don't mind, but I'm going to edit this issue to phrase it as a feature request instead. That way we can track how many others are interested in this feature. Thanks!

[asasas234]

@aimichelle I think only read-only access is needed, because if you have write access, read access is usually required.