Restyling of messages

In the Channel Manager a lot of question messages (aka confirmation messages) are used. Like the 'Discard changes?' message that appears when you click the Discard button in the visual editor, or the 'Save document changes?' message that appears for instance when you click an edit content button or try to switch projects while having another document open in the visual editor. As part of the restyling effort these messages need the following changes:

• New style outlined buttons
• Default button must be filled primary blue button
• Title semibold 16px i/o 20 px
• Body text font 14px i/o 16px