Allow admin to list accounts

[nombrekeff]

Admin can't list accounts at the moment, only superadmins can. We need this for logictraders API, so admin can show accounts and allow admins to select an owner when creating certain resources. ie. when creating an instance/bill

There are a couple of issues that depend on this:

• https://github.com/QbitArtifacts/logitraders-panel/issues/41 (to select the account to create a bill for)
• https://github.com/QbitArtifacts/logitraders-panel/issues/42 (to select the account to create an instance for)
• https://github.com/QbitArtifacts/logitraders-panel/issues/28 (to list accounts)

[santoslluis]

resolved in #23