CLI: Add Import XML command (#3572)

The CLI now contains an "import" command that creates a new database from the specified XML export. The new database is in kdbx 4 format, and does not currently accept a keyfile in database creation.

This change is required to create new databases from XML backups.

Fixes #2458

src/cli/Utils.h

@@ -40,6 +40,7 @@ namespace Utils
 
     void setStdinEcho(bool enable);
     QString getPassword(FILE* outputDescriptor = STDOUT);
+    QSharedPointer<PasswordKey> getPasswordFromStdin();
     int clipText(const QString& text);
     QSharedPointer<Database> unlockDatabase(const QString& databaseFilename,
                                             const bool isPasswordProtected = true,