boards: arm: add BeagleConnect Freedom

Add support for BeagleConnect Freedom, a TI CC1352P7 based development
board with enclosure and antenna featuring BLE and SubGHz wireless, 2x
mikroBUS sockets, external flash, light, temperature/humidity sensors,
USB-to-UART bridge, buzzer and battery charger.

See https://beagleconnect.org for details.

Previous closed pull requests:
* https://github.com/zephyrproject-rtos/zephyr/pull/38718
* https://github.com/zephyrproject-rtos/zephyr/pull/36703



Cc: Chris Friedt <chris@friedt.co>
Signed-off-by: Jason Kridner <jkridner@beagleboard.org>
Signed-off-by: Vaishnav Achath <vaishnav@beagleboard.org>
Signed-off-by: Erik Larson <erik@statropy.com>
Signed-off-by: Yadnik Bendale <yadnik22@gmail.com>
Signed-off-by: Baozhu Zuo <zuobaozhu@gmail.com>