Remove contributors section (boiler plate text)

See merge request docs/docs.beagleboard.io!62

Basic beagleplay greybus demo docs

See merge request !61

Signed-off-by: Ayush Singh <ayushdevel1325@gmail.com>

These adjustments makes preview much better on HTML render.

Signed-off-by: Ayush Singh <ayushdevel1325@gmail.com>

- Fixed some problems found during testing
- Mikrobus driver is not present in 6.6 kernel yet, so need to wait or
  add instructions to compile driver out of tree.

Signed-off-by: Ayush Singh <ayushdevel1325@gmail.com>