Mailbox sensor - notifier

[130s]

As struggling in #729 ring.com's mailbox sensor has become intolerable. Time to look for alternatives.

Reqs:

• Wirelessly report open/close of mailbox lid.
• (Ideally) Notify and triggers a camera to capture the footage.

[130s]

Hometech.com guys were praising LoRa sensor https://hackaday.com/2020/02/15/aaa-powered-lora-mailbox-sensor-goes-the-distance/