feat(search): search history bottom sheet

Record queries on explicit search and keep up to 100 entries.
Show them in a bottom sheet opened from the search bar, with
per-entry removal and clear-all.

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

@@ -16,6 +16,9 @@
     <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="recent_searches">Search history</string>
+    <string name="clear_search_history">Clear</string>
+    <string name="remove_search_history_entry">Remove from history</string>
     <string name="article_return_to_search">Return to search</string>
     <string name="error_checking_dictionaries">Failed to check dictionary status</string>
     <string name="error_loading_article">Loading error: %1$s</string>