Add guest mode functionality (2/3)

Add a flag to enable() to start Bluetooth in restricted
mode. In restricted mode, all devices that are paired during
restricted mode are deleted upon leaving restricted mode.
Right now restricted mode is only entered while a guest
user is active.

Bug: 27410683
Change-Id: I8f23d28ef0aa3a8df13d469c73005c8e1b894d19

static void btif_read_le_key(const uint8_t key_type, const size_t key_len, bt_bdaddr_t bd_addr,
 const uint8_t addr_type, const bool add_key, bool *device_added, bool *key_found)
{
    assert(device_added);
    assert(key_found);

 char buffer[100];
    memset(buffer, 0, sizeof(buffer));

 if (btif_storage_get_ble_bonding_key(&bd_addr, key_type, buffer, key_len) == BT_STATUS_SUCCESS)
 {
 if (add_key)
 {
            BD_ADDR bta_bd_addr;
            bdcpy(bta_bd_addr, bd_addr.address);

 if (!*device_added)
 {
                BTA_DmAddBleDevice(bta_bd_addr, addr_type, BT_DEVICE_TYPE_BLE);
 *device_added = true;
 }

 char bd_str[20] = {0};
            BTIF_TRACE_DEBUG("%s() Adding key type %d for %s", __func__,
                key_type, bdaddr_to_string(&bd_addr, bd_str, sizeof(bd_str)));
            BTA_DmAddBleKey(bta_bd_addr, (tBTA_LE_KEY_VALUE *)buffer, key_type);
 }

 *key_found = true;
 }
}

static void btif_read_le_key(const uint8_t key_type, const size_t key_len, bt_bdaddr_t bd_addr,
 const uint8_t addr_type, const bool add_key, bool *device_added, bool *key_found)
{
    assert(device_added);
    assert(key_found);

 char buffer[100];
    memset(buffer, 0, sizeof(buffer));

 if (btif_storage_get_ble_bonding_key(&bd_addr, key_type, buffer, key_len) == BT_STATUS_SUCCESS)
 {
 if (add_key)
 {
            BD_ADDR bta_bd_addr;
            bdcpy(bta_bd_addr, bd_addr.address);

 if (!*device_added)
 {
                BTA_DmAddBleDevice(bta_bd_addr, addr_type, BT_DEVICE_TYPE_BLE);
 *device_added = true;
 }

 char bd_str[20] = {0};
            BTIF_TRACE_DEBUG("%s() Adding key type %d for %s", __func__,
                key_type, bdaddr_to_string(&bd_addr, bd_str, sizeof(bd_str)));
            BTA_DmAddBleKey(bta_bd_addr, (tBTA_LE_KEY_VALUE *)buffer, key_type);
 }

 *key_found = true;
 }
}
