* Clarity edit for BLE tracker
The wording at the start confuses everybody who _doesn't_ use the Core install. Given those are the exceptions, not the default, rewording the start and moving the Core steps to the end. If/when this is approved I'll do a similar edit to the BT tracker docs.
* Add headings
Co-authored-by: Fabian Affolter <mail@fabian-affolter.ch>
* Add battery status to bluetooth_le tracker
Added a parameter to enable the Bluetooth LE device tracker to check
the battery status of tracked devices.
* Improve documentation after PR changes