chore: remove presearch engine

Removing the presearch engine and configuration because it got shutdown.

ref.: https://news.presearch.io/a-message-from-the-presearch-team-aaa448052b2b
https://x.com/presearchnews/status/2080744472791441807

searx/settings.yml

@@ -2016,41 +2016,6 @@ engines:
     shortcut: poc
     disabled: true
 
-  - name: presearch
-    engine: presearch
-    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
-    shortcut: psimg
-    disabled: true
-
-  - name: presearch videos
-    engine: presearch
-    network: presearch
-    search_type: videos
-    categories: [general, web]
-    timeout: 4.0
-    shortcut: psvid
-    disabled: true
-
-  - name: presearch news
-    engine: presearch
-    network: presearch
-    search_type: news
-    categories: [news, web]
-    timeout: 4.0
-    shortcut: psnews
-    disabled: true
-
   - name: pub.dev
     engine: xpath
     shortcut: pd