[simple theme] rework select; add safesearch to search and replace / with › in article url

* rework selection UI in pref (fix based on: https://github.com/twelsby/searx/commit/78643e9f43a103c523f112e9f3ce26a5c7bb3a0f)
* moved search filters underneath categories
* cut params from url and replace / with ›
* make h3 and url in article bigger
* add safe search select to search filter (this will not override settings and only be valid while on result page in a session)
* make search form button not overlap each other when js is disabled
* 1rem padding around preview image and thumbnail in default article template

searx/webapp.py

@@ -419,6 +419,16 @@ def _get_enable_categories(all_categories):
     return [x for x in all_categories if x in enabled_categories]
 
 
+def get_pretty_url(parsed_url):
+    path = parsed_url.path
+    path = path[:-1] if len(path) > 0 and path[-1] == '/' else path
+    path = path.replace("/", " › ")
+    return [
+        parsed_url.scheme + "://" + parsed_url.netloc,
+        path
+    ]
+
+
 def render(template_name, override_theme=None, **kwargs):
     # values from the HTTP requests
     kwargs['endpoint'] = 'results' if 'q' in kwargs else request.endpoint
@@ -457,6 +467,7 @@ def render(template_name, override_theme=None, **kwargs):
     kwargs['searx_version'] = VERSION_STRING
     kwargs['searx_git_url'] = GIT_URL
     kwargs['get_setting'] = get_setting
+    kwargs['get_pretty_url'] = get_pretty_url
 
     # helpers to create links to other pages
     kwargs['url_for'] = url_for_theme  # override url_for function in templates