net: openthread: Add openthread TCAT implementation.

This commit adds bbtc implementation.
New file in modules/openthread/platform/ble.c
New corresponding kconfig option `OPENTHREAD_BLE_TCAT`.

Co-authored-by: Piotr Jasiński <piotr.jasinski@nordicsemi.no>

Signed-off-by: Przemyslaw Bida <przemyslaw.bida@nordicsemi.no>
Signed-off-by: Piotr Jasiński <piotr.jasinski@nordicsemi.no>