Separate client.admin concerns and users

Is this a bug report or feature request?

• Feature Request

What should the feature do:

Ceph has advised that all users/actors in a system should have their own client, which includes Rook. This can be important for audit logs.

Today, all usage of admin permissions are used via client.admin. This includes operations Rook iself is doing, OSD init that uses client.admin to get up-to-date OSD keyrings, and the Rook toolbox. Possibly others.

Ceph has advised that client.admin should not be regularly used for anything. It should essentially just be securely stored for emergencies. This is asking for quite a change from Rook's current mechanisms. It should be taken on only with great care, and we must ensure that cephx key rotation is not broken by any changes we might make.

What is use case behind this feature:

Improve auditing.

Environment: