- Added `migrate_to_sqlite.py` to handle migration of user stats and session logs from text files to an SQLite database.
- The script reads XP, level, and total time from respective text files and saves them into the `user_stats` table in the SQLite database.
- Session logs are parsed and logged into the `session_log` table.
- Existing text files are deleted after successful migration.
- Created a new SQLite database file `rhel_learning.db` with tables for questions, user stats, and session logs.
