feat(settings): place the search bar at the top or the bottom

Add a search bar position setting and render the bar above the
results or below them, with window insets applied to match.

app/src/main/res/values/strings.xml

@@ -12,6 +12,9 @@
     <string name="language_english">English</string>
     <string name="language_russian">Russian</string>
     <string name="language_system">System</string>
+    <string name="search_bar_position">Search bar</string>
+    <string name="search_bar_position_top">Top</string>
+    <string name="search_bar_position_bottom">Bottom</string>
     <string name="clear_search">Clear search</string>
     <string name="article_return_to_search">Return to search</string>
     <string name="error_checking_dictionaries">Failed to check dictionary status</string>