CLI: Use stderr for password prompt

Fixes #3398.

Convert to QTextStream for all CLI IO and greatly improve CLI tests

* Completely overhaul CLI tests to be much more streamlined and easy to read. Removed unnecessary code blocks by using existing functions.

Co-authored-by: Emma Brooks <me@pluvano.com>

src/cli/Info.cpp

@@ -33,7 +33,7 @@ Info::Info()
 
 int Info::executeWithDatabase(QSharedPointer<Database> database, QSharedPointer<QCommandLineParser>)
 {
-    TextStream out(Utils::STDOUT, QIODevice::WriteOnly);
+    auto& out = Utils::STDOUT;
 
     out << QObject::tr("UUID: ") << database->uuid().toString() << endl;
     out << QObject::tr("Name: ") << database->metadata()->name() << endl;