[mod] Adds Lingva translate engine

Add the lingva engine (which grabs data from google translate).  Results from
Lingva are added to the infobox results.

searx/engines/lingva.py

@@ -0,0 +1,68 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+# lint: pylint
+"""Lingva (alternative Google Translate frontend)"""
+
+from json import loads
+
+about = {
+    "website": 'https://lingva.ml',
+    "wikidata_id": None,
+    "official_api_documentation": 'https://github.com/thedaviddelta/lingva-translate#public-apis',
+    "use_official_api": True,
+    "require_api_key": False,
+    "results": 'JSON',
+}
+
+engine_type = 'online_dictionary'
+categories = ['general']
+
+url = "https://lingva.ml"
+search_url = "{url}/api/v1/{from_lang}/{to_lang}/{query}"
+
+
+def request(_query, params):
+    params['url'] = search_url.format(
+        url=url, from_lang=params['from_lang'][1], to_lang=params['to_lang'][1], query=params['query']
+    )
+    return params
+
+
+def response(resp):
+    results = []
+
+    result = loads(resp.text)
+    info = result["info"]
+    from_to_prefix = "%s-%s " % (resp.search_params['from_lang'][1], resp.search_params['to_lang'][1])
+
+    if "typo" in info:
+        results.append({"suggestion": from_to_prefix + info["typo"]})
+
+    if 'definitions' in info:  # pylint: disable=too-many-nested-blocks
+        for definition in info['definitions']:
+            if 'list' in definition:
+                for item in definition['list']:
+                    if 'synonyms' in item:
+                        for synonym in item['synonyms']:
+                            results.append({"suggestion": from_to_prefix + synonym})
+
+    infobox = ""
+
+    for translation in info["extraTranslations"]:
+        infobox += f"<b>{translation['type']}</b>"
+
+        for word in translation["list"]:
+            infobox += f"<dl><dt>{word['word']}</dt>"
+
+            for meaning in word["meanings"]:
+                infobox += f"<dd>{meaning}</dd>"
+
+            infobox += "</dl>"
+
+    results.append(
+        {
+            'infobox': result["translation"],
+            'content': infobox,
+        }
+    )
+
+    return results

searx/settings.yml

@@ -886,6 +886,12 @@ engines:
     shortcut: loc
     categories: images
 
+  - name: lingva
+    engine: lingva
+    shortcut: lv
+    # set lingva instance in url, by default it will use the official instance
+    # url: https://lingva.ml
+
   - name: lobste.rs
     engine: xpath
     search_url: https://lobste.rs/search?utf8=%E2%9C%93&q={query}&what=stories&order=relevance