Refactor the dashboard to work with different roles

[troccoli]

The Dashboard and all the various CRUD screens need to check if the logged-in user can do the operations. This is not only for the whole page, but for the operations of the specific items in the list.

For example, if there are two seasons and I am logged in as Season 1 Administrator, then in the Seasons screen I will see both seasons but the buttons to see the competitions, edit and delete season 2 will be disabled, as I don't have permissions. Also the button to delete season 1 will be disabled too, again as I don't have permission.

If I am logged in as Competition 1 Administrator, where the competition is in season 1, then in the Seasons screen I will only see season 1, with the edit and delete button disabled. And when I click on the competitions button I will see all competitions, but only the buttons to see the divisions and edit competitions 1 will be enabled, as those are the only permissions I have.