gui: added ChatWidgetContainerHandlerMapper

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
gui: remove ChatWidgetActions from ChatWidgetManager

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
gui: fixed connections to chatWidgetCreated and chatWidgetDestroyed signals

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
gui: rename chatWidgetCreated/Destroyed to chatWidgetAdded/Removed

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
gui: changed some logic in ChatWidgetManager and Repository

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
gui: remove singleton from ChatWidgetManager

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>