Create SuperAdmin role

[carlsednaoui]

As a SuperAdmin I want to be able to edit any organization, event or user role.

• I should be able to give SuperAdmin right to other users
• I should be able to manage which organizations an OrganizationAdmin can manage
• I should be able to manage which organizations a volunteer is interested in
• I should be able to manage any organization or event information

[carlsednaoui]

This issue is outdated. Please refer to #20.