Clarity edit for BLE tracker (#15589)

* 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>

source/_integrations/bluetooth_le_tracker.markdown

@@ -12,16 +12,11 @@ This tracker discovers new devices on boot and in regular intervals and tracks B
 
 Devices discovered are stored with 'BLE_' as the prefix for device mac addresses in `known_devices.yaml`.
 
-This platform requires pybluez to be installed. On Debian based installs, run
+## Setup
 
-```bash
+This platform requires pybluez to be installed, which is already the case if you're using Home Assistant OS, Supervised or Container. For Home Assistant Core installs see below on the required steps.
-sudo apt install bluetooth
-```
 
-Before you get started with this platform, please note that:
+## Configuration
-
- - This platform is incompatible with Windows
- - This platform requires access to the Bluetooth stack, see [Rootless Setup section](#rootless-setup) for further information
 
 To use the Bluetooth tracker in your installation, add the following to your `configuration.yaml` file:
 
@@ -59,7 +54,22 @@ Some BTLE devices (e.g., fitness trackers) are only visible to the devices that
 
 Enabling the battery tracking might slightly decrease the duration of the battery, but since this is only done at most once a day, this shouldn't be noticeable. Not all devices offer battery status information; if the information is not available, the integration will only try once at startup.
 
-## Rootless Setup
+For additional configuration variables check the [Device tracker page](/integrations/device_tracker/).
+
+## Home Assistant Core installs
+
+On Debian based Home Assistant Core installations, run:
+
+```bash
+sudo apt install bluetooth
+```
+
+Before you get started with this platform, please note that:
+
+ - This platform is incompatible with Windows
+ - This platform requires access to the Bluetooth stack, see [Rootless Setup section](#rootless-setup) for further information
+
+### Rootless Setup on Core installs
 
 Normally accessing the Bluetooth stack is reserved for root, but running programs that are networked as root is a bad security wise. To allow non-root access to the Bluetooth stack we can give Python 3 and hcitool the missing capabilities to access the Bluetooth stack. Quite like setting the setuid bit (see [Stack Exchange](https://unix.stackexchange.com/questions/96106/bluetooth-le-scan-as-non-root) for more information).
 
@@ -70,5 +80,3 @@ sudo setcap 'cap_net_raw+ep' $(readlink -f $(which hcitool))
 ```
 
 A restart of Home Assistant is required.
-
-For additional configuration variables check the [Device tracker page](/integrations/device_tracker/).