Implement Holiday/Away Mode ✈

[dannytsang]

Create a mode to cater for when people are not at home.

At the moment, it can use presence to detect when no one is at home but this should also add other features like fake presence - make it look like as if someone is at home.

Goals

• [x] Manually set holiday mode (stepping stone)
• [x] Use geolocation to set holiday mode
• [x] Automate alarm based on holiday schedule
• [ ] Use calendar integration to set holiday mode
• [x] Set HVAC
• [x] Reset holiday mode on the way back home.

[dannytsang]

Cannot rely on partner's phone sensor because the OnePlus 6T seems to have very aggressive battery saving mode even when it's not in low battery mode to the point where some notifications in other apps don't show up. This limits the possibility of calculating things like distance from home, vector, etc.