[enh] add npm search engine (#1510)

searx/settings.yml

@@ -428,11 +428,25 @@ engines:
     engine : mixcloud
     shortcut : mc
 
+  - name : npm
+    engine : json_engine
+    paging : True
+    search_url : https://api.npms.io/v2/search?q={query}&size=25&from={pageno}
+    results_query : results
+    url_query : package/links/npm
+    title_query : package/name
+    content_query : package/description
+    page_size : 25
+    categories : it
+    disabled: True
+    timeout: 5.0
+    shortcut : npm
+
   - name : nyaa
     engine : nyaa
     shortcut : nt
     disabled : True
-  
+
   - name : acgsou
     engine : acgsou
     shortcut : acg