Notification screen at max brightness when walking

[SteveAmor]

This is possibly a proof of concept and I am more than open to any feedback on the code and/or enhancements/changes.

I usually have my Pinetime on Low brightness but when I'm walking outside and get notifications I put the brightness on High so I can read them in the light. Given there's no ambient light detector, I realised I could check if I'm walking so I've created this PR.

It would be great if it did make it into the main branch but it's possibly an unusual user case. and there's no settings for it. You can select Motion Auto Bright (MAB) in the Display settings screen to toggle it on and off.

Essentially, if you are walking and you get a notification (or check your notifications), the screen will be at max brightness. There's a 510 second decay for the last time your steps increased to keep this feature "active". After that, notifications will appear at normal brightness.

There may be scope for more types of activities to be triggered in the MotionController.
This PR may also give some ideas for the PTPro.

[github-actions]

Build size and comparison to main:

Section	Size	Difference
text	380200B	196B
data	936B	0B
bss	22952B	16B

Run in InfiniEmu

[SteveAmor]

Toggle for Motion Auto Bright (MAB)

[mark9064]

Could adding in a daytime check using the sunset/sunrise time be a good addition? Haven't actually tried this but seems like it might avoid being super bright when walking at night. Might be overcomplicating things though