…cRoom table creation scripts. This new field determines whether a room's chat history is preserved or removed upon its deletion.

…eHistOnRoomDeletion field.[C

…e MUCRoom class so it can be accessed during runtime.

…r to use the new preserveHistOnRoomDeletion field for processing room configuration.

…Manager to load and store room settings and history, incorporating the new preserveHistOnRoomDeletion field. 2. Add functionality to remove room history stored in ofMucConversationLog upon room deletion. 3. Add the new preserveHistOnRoomDeletion field to the MUC default room settings screen, as well as to the room edit and creation screens.

Add a preserveHistOnDel field to the OfMucRoom table to specify chat history preservation on the deletion of a chat room.
Updated MUCPersistenceManager to make use of the new preserveHistOnDel field.

Changing muc#roomconfig_preservehistondel to {http://igniterealtime.org}muc#roomconfig_preservehistondel as it is a third party field.