[SQLiteCache] Check sqlite3 extension in __construct
[SQLiteCache] Check sqlite3 extension in __construct

Checks if the sqlite3 extension is loaded and throws an error
if it's missing.

ORelio/rss-bridge,Frenzie/rss-bridge,simonbru/rss-bridge,kranack/rss-bridge,Riduidel/rss-bridge,ORelio/rss-bridge,kranack/rss-bridge,kranack/rss-bridge,Riduidel/rss-bridge,RSS-Bridge/rss-bridge,RSS-Bridge/rss-bridge,RSS-Bridge/rss-bridge,ORelio/rss-bridge,sebsauvage/rss-bridge,Frenzie/rss-bridge,kranack/rss-bridge,Riduidel/rss-bridge,simonbru/rss-bridge