Until now the OOB info and URI fields in unprovisioned beacons were
generally ignored by the implementation. Add fields for these to
bt_mesh_prov and make sure to take them into account when encoding
advertising data, both for PB-ADV and PB-GATT. For PB-ADV the URI goes
out in a separate beacon, whereas for PB-GATT it is placed in the scan
response data.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>