This renames the two functions we have to translate between UI and
DB permissions, as well as some of their associated variables to
make it clearer which kind of permission they contain.
We don't use this term consistently and it's not defined anywhere.
Since most of the Admin app deals with user-facing permssions, it's
OK to just use the term "permissions". Where both types of permission
are present in the same file, we can more clearly distinguish them
as "UI permissions" and "DB permissions".
These are more than a list of permissions: each item includes the
label to use when displaying it as an option on a form. Switching
to a name that reflects how the attributes are used will help to
avoid confusion when we rename some of the other attributes in the
same file in later commits.
