chat: remove invalid qDeleteAll calls

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

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

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
chat: use ChatStyle to store current chat style

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
chat: remove unused methods from ChatStyleEngine

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
gui: remove probably confusing behavior

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
fixup! chat: remove unused methods from ChatStyleEngine

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
chat: use ChatStyle as parameter in createRenderer

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