[BalooRolesProvider] Use Property IDs instead of string matching

[BalooRolesProvider] Use Property IDs instead of string matching

Instantiating KFileMetaDataInfo for each file and property, even when
the role is not used, is somewhat expensive and unnecessary. Use the
numeric Property ID to map it to a role, and only instantiate the used
PropertyInfo's.

Remove the properties provided by KFM::UserMetaData from the map, as
these will newer match.