This patch introduces new `campaigns:get_all` and `campaigns:manage_all`
permissions which alter the behaviour of the the old `campaigns:get` and
`campaigns:manage` permissions. This is a subtle breaking behavioural change.
Old:
- `campaigns:get` -> View all campaigns irrespective of a user's list
permissions.
- `campaigns:manage` -> Manage all campaigns irrespective of a user's list
permissions.
New:
- `campaigns:get_all` -> View all campaigns irrespective of a user's list
permissions.
- `campaigns:manage_all` -> Manage all campaigns irrespective of a user's list
permissions.
- `campaigns:get` -> View only the campaigns that have at least one list to
which which a user has get or manage access.
- `campaigns:manage` -> Manage only the campaigns that have at list one list
to which a user has get or manage access.
In addition, this patch refactors and cleans up certain permission related
logic and functions.
