Upgrade SQLite to MySQL back end

[spoulson]

SQLite is the current choice of database storage for simplicity of storing session state and history. However, it lacks multiuser capability in high user access environments. This can cause stability issues with clients as they experience access locks due to race conditions with other users.

Instead, this data should be hosted in a MySQL database.

Also, it is not ideal to maintain an open data access layer strategy. Design MySQL as the only data access layer.