Add permission to validators

We start refactoring the validators by adding to it the ability to track
which permissions (admin/user) it needs in order to complete it work.

In future patches, we will actually implement this differentiation between
admin/user validators and more the validation procedure to BenchmarkEngine.

Change-Id: I27216ed9c610a1cfd44789ff4ff8c5f3ff10258a
Merge "Add permission to validators"