Ability to provide the "authoritativeConcept" parameter to distinguish Concepts in tested scheme vs. aligned concepts

[tfrancart]

See https://github.com/cmader/qSKOS/blob/master/README.rdoc#label-What+are+-22Authoritative+Concepts-22-3F

qSkos guesses which concepts are "authoritatives" vs. concepts that are "external" by examining the host part of the URI only. This is problematic when checking mapping relations between vocabularies that are in the same namespace : since RDFS inference is applied, mapped URIs are typed Concept, and if they have the same base URI, they are validated as well as authoritative concepts.

An option should be added to the input form to provide the substring of the URI that defines which are authoritative concepts.