[mod] engines: remove stract engine (#5800)

Engine probably dead, developer doesn't have time to maintain it anymore:

- https://github.com/StractOrg/stract/issues/267

Related:

- https://github.com/searxng/searxng/pull/3099

searx/settings.yml

@@ -33,7 +33,7 @@ search:
   # Filter results. 0: None, 1: Moderate, 2: Strict
   safe_search: 0
   # Existing autocomplete backends: "360search", "baidu", "brave", "dbpedia", "duckduckgo", "google", "yandex",
-  # "mwmbl", "naver", "seznam", "sogou", "startpage", "stract", "swisscows", "quark", "qwant", "wikipedia" -
+  # "mwmbl", "naver", "seznam", "sogou", "startpage", "swisscows", "quark", "qwant", "wikipedia" -
   # leave blank to turn it off by default.
   autocomplete: ""
   # minimun characters to type before autocompleter starts
@@ -2498,11 +2498,6 @@ engines:
       results: HTML
       language: de
 
-  - name: stract
-    engine: stract
-    shortcut: str
-    disabled: true
-
   - name: svgrepo
     engine: svgrepo
     shortcut: svg