[enh] Add whaleslide.com (#2861)

Upstream example: https://whaleslide.com/search/web/runlevels

Co-authored-by: Noémi Ványi <kvch@users.noreply.github.com>

searx/settings.yml

@@ -1377,6 +1377,27 @@ engines:
       require_api_key: false
       results: html
 
+  - name : whaleslide
+    shortcut : whale
+    engine : json_engine
+    paging : True
+    # This API Token is needed to work
+    search_url : https://search.whaleslide.com/api/v1/search_v2/web/{pageno}?q={query}&api_token=f8OhUDEYKUICHDnIxEgI7Cb4uYyTBqT4nO8iueNbfTO3devS24yElGqM7nCm
+    url_query : url
+    title_query : title
+    title_html_to_text : True
+    content_query : abstract
+    content_html_to_text : True
+    categories : general
+    disabled : True
+    about:
+      website: https://whaleslide.com/
+      wikidata_id: # No Wikidata page
+      official_api_documentation: false
+      use_official_api: false
+      require_api_key: false
+      results: JSON
+
   - name : petal
     shortcut : petal
     engine : xpath