Merge "Add extractBE to the Bluetooth Packets Iterators"

system/packet/avrcp/avrcp_browse_packet.cc

system/packet/avrcp/avrcp_packet.h

system/packet/avrcp/change_path.cc

system/packet/avrcp/get_element_attributes_packet.cc

system/packet/avrcp/get_folder_items.cc

system/packet/avrcp/get_item_attributes.cc

system/packet/avrcp/play_item.cc

system/packet/avrcp/register_notification_packet.cc

system/packet/avrcp/set_addressed_player.cc

system/packet/avrcp/set_browsed_player.cc

system/packet/avrcp/vendor_packet.cc

system/packet/base/iterator.h

system/packet/tests/base/iterator_test.cc