Review FD UI for disabled fields

The idea is to improve the UI of FusionDirectory when it’s used with a non-admin account, including:

1. When all fields are read-only
2. When only a few fields are readable/writable

Actual behavior

UI is the same as the admin with greyed-out fields for non-writable and non-readable fields

Expected behavior

Ideas:

1. Have a special class for form element which should only show for writable attributes, like the add/remove buttons on SetAttributes (easy to do for linearRendering=TRUE, but requires some coding/thinking for linearRendering=FALSE)
2. Have a special class for non-readable attributes, allowing to hide them completely
3. Alter CSS so that non-writable inputs are easy to read and not confusing (this means they need a special class as well be distinguishable from disabled fields)
4. Must star should be added by CSS, not smarty (not directly related but requires the same kind of code changes)

Difficulties

1. We need to avoid empty sections
2. Hiding/removing an empty section may mess the layout
3. Managed attributes may need to be exempted of these changes
4. When hiding an input we need to hide the label as well