beagleplay: demo: Add low power video doorbell

See merge request docs/docs.beagleboard.io!104

Add a bunch of todo items and case fixups.
Also add a few links and info on how to write systemd shellscript

Signed-off-by: Dhruva Gole <d-gole@ti.com>

Fix formatting in BeagleBone Blue firmware flashing page (flashing-firmware.rst)

See merge request docs/docs.beagleboard.io!106

Add docs for low power video doorbell demo made at EOSS 2024

Signed-off-by: Dhruva Gole <d-gole@ti.com>

Small Spelling and Flow Changes

See merge request docs/docs.beagleboard.io!103

Docs updates - chapter restructuring, images, and more

See merge request docs/docs.beagleboard.io!89