[mod] presearch: set WEB timeout to 4sec & single network for all request

timeout: 4.0
  The timeout of presearch-WEB is left up from the default of 3sec to 4sec.  The
  engine has to send two HTTP requests, they often exceed the default timeout of
  3sec. Since all other presearch categories (images, videos, news) also have a
  timeout of 4 sec, the WEB search should also have the same timeout.

network: presearch
  Place all HTTP requests in the same network, named ``presearch``.

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/settings.yml

@@ -1347,10 +1347,12 @@ engines:
     search_type: search
     categories: [general, web]
     shortcut: ps
+    timeout: 4.0
     disabled: true
 
   - name: presearch images
     engine: presearch
+    network: presearch
     search_type: images
     categories: [images, web]
     timeout: 4.0
@@ -1359,6 +1361,7 @@ engines:
 
   - name: presearch videos
     engine: presearch
+    network: presearch
     search_type: videos
     categories: [general, web]
     timeout: 4.0
@@ -1367,6 +1370,7 @@ engines:
 
   - name: presearch news
     engine: presearch
+    network: presearch
     search_type: news
     categories: [news, web]
     timeout: 4.0