Lun 1563

Make sure the length of the auto-generated site permissions do not exceed the maximum length of the DB field.
I don't want to over-engineer this piece of logic. Reasons:
- length (role name) = 50
- there are 4 role entries in the system
- role name has a uniqueness constraint
- site domain length = 80 and also has a uniqueness constraint (true, in the validation logic, not in the DB)
- the tail is unique: it's the site id
- there is no possibility to overflow
- there is only a theoretical possibility to have 2 identic entries, if all the following hold:
        - the role name length is changed to something > 75: highly unlikely, we have 4 entries in total and the biggest has 10 chars ('site admin')
        - there are at least 2 role entries whose first 74+ chars are identical (this implies a very stupid admin)

We don't have this kind of data validation in other parts of the application, so I prefer to have a clear code if not necessary.

Normally, when somebody wants to make some column values (which relate to other columns in other tables) more readable, he keeps the fk1-fk2 notation and joins the 2 related columns in the view logic. This makes it unnecessary to update the values of the column whenever the values in the related fields change.

Conclusion: I want to keep this as simple as possible, so that I don't have to over-complicate the logic; if for instance I want to make a filter after these entries, I would have to apply the same logic for constructing the query. At least I have now this logic in its own function, but the best case would still be to have kept the fk1-fk2 notation. It's unique and simple.