[enh] settings.yml: add use_default_settings option (2nd version)

tests/unit/settings/syntaxerror_settings.yml

@@ -0,0 +1,2 @@
+Test:
+  **********

tests/unit/settings/user_settings.yml

@@ -0,0 +1,111 @@
+general:
+    debug : False
+    instance_name : "searx"
+
+search:
+    safe_search : 0
+    autocomplete : ""
+    default_lang : ""
+    ban_time_on_fail : 5
+    max_ban_time_on_fail : 120
+
+server:
+    port : 9000
+    bind_address : "0.0.0.0"
+    secret_key : "user_settings_secret"
+    base_url : False
+    image_proxy : False
+    http_protocol_version : "1.0"
+    method: "POST"
+    default_http_headers:
+        X-Content-Type-Options : nosniff
+        X-XSS-Protection : 1; mode=block
+        X-Download-Options : noopen
+        X-Robots-Tag : noindex, nofollow
+        Referrer-Policy : no-referrer
+
+ui:
+    static_path : ""
+    templates_path : ""
+    default_theme : oscar
+    default_locale : ""
+    theme_args :
+        oscar_style : logicodev
+
+engines:
+  - name : wikidata
+    engine : wikidata
+    shortcut : wd
+    timeout : 3.0
+    weight : 2
+
+  - name : wikibooks
+    engine : mediawiki
+    shortcut : wb
+    categories : general
+    base_url : "https://{language}.wikibooks.org/"
+    number_of_results : 5
+    search_type : text
+
+  - name : wikinews
+    engine : mediawiki
+    shortcut : wn
+    categories : news
+    base_url : "https://{language}.wikinews.org/"
+    number_of_results : 5
+    search_type : text
+
+  - name : wikiquote
+    engine : mediawiki
+    shortcut : wq
+    categories : general
+    base_url : "https://{language}.wikiquote.org/"
+    number_of_results : 5
+    search_type : text
+
+locales:
+    en : English
+    ar : العَرَبِيَّة (Arabic)
+    bg : Български (Bulgarian)
+    bo : བོད་སྐད་ (Tibetian)
+    ca : Català (Catalan)
+    cs : Čeština (Czech)
+    cy : Cymraeg (Welsh)
+    da : Dansk (Danish)
+    de : Deutsch (German)
+    el_GR : Ελληνικά (Greek_Greece)
+    eo : Esperanto (Esperanto)
+    es : Español (Spanish)
+    et : Eesti (Estonian)
+    eu : Euskara (Basque)
+    fa_IR : (fārsī) فارسى (Persian)
+    fi : Suomi (Finnish)
+    fil : Wikang Filipino (Filipino)
+    fr : Français (French)
+    gl : Galego (Galician)
+    he : עברית (Hebrew)
+    hr : Hrvatski (Croatian)
+    hu : Magyar (Hungarian)
+    ia : Interlingua (Interlingua)
+    it : Italiano (Italian)
+    ja : 日本語 (Japanese)
+    lt : Lietuvių (Lithuanian)
+    nl : Nederlands (Dutch)
+    nl_BE : Vlaams (Dutch_Belgium)
+    oc : Lenga D'òc (Occitan)
+    pl : Polski (Polish)
+    pt : Português (Portuguese)
+    pt_BR : Português (Portuguese_Brazil)
+    ro : Română (Romanian)
+    ru : Русский (Russian)
+    sk : Slovenčina (Slovak)
+    sl : Slovenski (Slovene)
+    sr : српски (Serbian)
+    sv : Svenska (Swedish)
+    te : తెలుగు (telugu)
+    ta : தமிழ் (Tamil)
+    tr : Türkçe (Turkish)
+    uk : українська мова (Ukrainian)
+    vi : tiếng việt (Vietnamese)
+    zh : 中文 (Chinese)
+    zh_TW : 國語 (Taiwanese Mandarin)

tests/unit/settings/user_settings_keep_only.yml

@@ -0,0 +1,14 @@
+use_default_settings:
+    engines:
+        keep_only:
+            - wikibooks
+            - wikinews
+server:
+    secret_key: "user_secret_key"
+    bind_address: "0.0.0.0"
+    default_http_headers:
+        Custom-Header: Custom-Value
+engines:
+    - name: wikipedia
+    - name: newengine
+      engine: dummy

tests/unit/settings/user_settings_remove.yml

@@ -0,0 +1,10 @@
+use_default_settings:
+    engines:
+        remove:
+            - wikibooks
+            - wikinews
+server:
+    secret_key: "user_secret_key"
+    bind_address: "0.0.0.0"
+    default_http_headers:
+        Custom-Header: Custom-Value

tests/unit/settings/user_settings_remove2.yml

@@ -0,0 +1,15 @@
+use_default_settings:
+    engines:
+        remove:
+            - wikibooks
+            - wikinews
+server:
+    secret_key: "user_secret_key"
+    bind_address: "0.0.0.0"
+    default_http_headers:
+        Custom-Header: Custom-Value
+engines:
+    - name: wikipedia
+      tokens: ['secret_token']
+    - name: newengine
+      engine: dummy

tests/unit/settings/user_settings_simple.yml

@@ -0,0 +1,6 @@
+use_default_settings: True
+server:
+    secret_key: "user_secret_key"
+    bind_address: "0.0.0.0"
+    default_http_headers:
+        Custom-Header: Custom-Value