Change button redirect to characters screen

[janrtvld]

Currently, when you're on the dashboard of the demo and you'll press change character it just wipes the state and starts fresh. It would be nice if we can drop the user directly into the onboarding flow at the character selection step.

We also keep track of the characters that the user has completed. We could add a checkmark to the characters that are already done?

• The onboardingSlice keeps track of the onboarding step that the user is on.
• We should create an redux action named something like 'demo/CHANGECHARACTER' that resets the current state and changes the onboarding step to 2 (PICK_CHARACTER).