Create shared logger daemon

The database should be shared between the Plasma Dialer and Spacebar. A logger daemon should be running all the time to catch incoming messages and calls and notify the user.

The following is a plan how this could work:

• Spacebar does not write to the database any more.
• It reads chat history directly from the database.
• It connects to the relevant TelepathyQt signals to get incoming messages while the app is running, but saving the messages is done by the logger, which is also running.
• The logger connects to the messageSent signal to store sent messages.
• The logger runs all the time to catch all incoming messages and writes them to the database.

Class struture: app:

• ChannelHandler
• ChatListModel
• ContactMapper
• MessageModel
• Utils

logger:

• Database
• yet-to-be-written-channel-handler-like-thing