Add first-time setup flow

[hughesjs]

The first time the app is launched we want to run the following:

• Welcome splash
• Get health integration permissions
• Get/Comfirm weight/height
• Find treadmill and store

[hughesjs]

@HoLuLuLu - Some of the work I've done for this is on first-launch and tbh I got a little stuck on the best way to pass the data between the screens and save it into the sql-lite at the end - I'm usually an enterprise dev, this is my first Flutter project - would you mind taking a look at that if you get the chance? It'll help unblock me on some other features when I next get a chance to look at this.

Also, if you're interested, we can have a chat about getting you added as a collaborator

[HoLuLuLu]

@hughesjs I'll try to help you, but I have to say this is my first flutter project too. So we will see how it turns out.

I would very much appreciate to be a collaborator to this project.

[hughesjs]

Sounds good to me :) I'll set up a discord or something for us when I get a sec and we can work together on it. Hopefully I'll have more time from the middle of next month once things have settled down for me