[feat] engines: add s1search general engine (#6186)

S1Search provides various different search services, which all seem
to be somewhat based on Google and Yahoo. The site looks kinda suspicious,
but the results are fine.

You can find a list of their engines by using a subdomain finder like
https://web-toolbox.dev/en/tools/subdomain-lookup and search for `s1search.co`.

searx/settings.yml

@@ -2845,6 +2845,38 @@ engines:
       website: https://minecraft.wiki/
       wikidata_id: Q105533483
 
+  # s1search google engines / mirrors
+  - name: searchtoday
+    engine: s1search
+    shortcut: std
+    base_url: https://info.searchtoday.site
+    disabled: true
+
+  # - name: webcrawler
+  #   engine: s1search
+  #   shortcut: wc
+  #   base_url: https://www.webcrawler.com
+  #   disabled: true
+
+  # s1search yahoo engines / mirrors
+  # - name: excite
+  #   engine: s1search
+  #   shortcut: exc
+  #   base_url: https://results.excite.com.s1search.co
+  #   disabled: true
+
+  # - name: metacrawler
+  #   engine: s1search
+  #   shortcut: mec
+  #   base_url: https://search.metacrawler.com
+  #   disabled: true
+
+  - name: infospace
+    engine: s1search
+    shortcut: ifs
+    base_url: https://search.infospace.com
+    disabled: true
+
 # Doku engine lets you access to any Doku wiki instance:
 # A public one or a privete/corporate one.
 #  - name: ubuntuwiki