Resolve "Rewrite registration wizard"

Closes #74 (closed)

aleksis/apps/paweljong/frontend/components/event/events.graphql

+query eventById($id: ID!) {
+  eventById(id: $id) {
+    id
+    displayName
+    description
+    cost
+    minCost
+    maxCost
+    terms {
+      id
+    }
+    additionalFields {
+      id
+    }
+  }
+}
+
+query eventBySlug($slug: String!) {
+  event: eventBySlug(slug: $slug) {
+    id
+    displayName
+    description
+    cost
+    minCost
+    maxCost
+    dateRetraction
+    terms {
+      id
+      title
+      term
+      confirmationText
+    }
+    additionalFields {
+      id
+      title
+      fieldType
+      required
+      helpText
+    }
+    contactInformationVisibleFields
+  }
+}