Add a boolean variable is_class

This allows to check if a selected resource_iri is a class or an
instance.
TODO: Should we add a flag for graph_iri, too?

src/components/InstanceList.vue

@@ -4,7 +4,7 @@ import QueryResultList from './QueryResultList.vue'
 </script>
 
 <template>
-  <QueryResultList title="Instance List" search :query="'select distinct ?instance { ?instance a <' + resource_iri + '> } order by ?instance'" select-variable="instance" itemClass="py-2" ref="instanceList" :activeResource="resource_iri" :selectResource="(iri) => {useSelectionStore().changeResourceIri(iri)}"  />
+  <QueryResultList title="Instance List" search :query="'select distinct ?instance { ?instance a <' + resource_iri + '> } order by ?instance'" select-variable="instance" itemClass="py-2" ref="instanceList" :activeResource="resource_iri" :selectResource="(iri) => {useSelectionStore().changeResourceIri(iri, false)}"  />
 </template>
 
 <script>

src/stores/selection.js

@@ -5,15 +5,21 @@ export const useSelectionStore = defineStore('selection', {
   state: () => ({
       graph_iri: config.graph_iri,
       resource_iri: config.resource_iri,
+      is_class: true,
   }),
   actions: {
     changeGraphIri (graphIri) {
       console.log('Change graph Iri to ' + graphIri)
       this.graph_iri = graphIri
     },
-    changeResourceIri (resourceIri) {
+    changeResourceIri (resourceIri, isClass=true) {
       console.log('Change resource Iri to ' + resourceIri)
       this.resource_iri = resourceIri
+      if (isClass == true) {
+        this.is_class = true
+      } else {
+        this.is_class = false
+      }
     }
   },
 })