Permission Schemes. Choosing Active schema

As an Admin I'd like to be able to choose an Active Permission Schema so that it's used in Poulpe and its components as default one
A boolean flag should be added making a schema being active.
Acceptance Criteria:

• A context menu item Activate should appear while clicking right mouse button on the permission schema. A confirmation window should also be there.
• Only one schema can be marked Active
• A special mark should be placed in the list of schemes marking active and non-active schemes.