hci_transport: extract convenience function declaration for h4, h5, em9304_spi, and usb into separate hci_transport_{type}.h

h4 posix ports: use btstack_uart_posix instead of btstack_uart_block_posix

Replaced HCI_PACKET_BUFFER_SIZE with HCI_INCOMING_PACKET_BUFFER_SIZE and HCI_OUTGOING_PACKET_BUFFER_SIZE

mtk: fix compile -> named union on btstack_data_source_t

mtk: fix compile

mtk: fix hci transport, daemon: fix compile

fix old contact email

runloop: enable callback for all data sources

runloop: pass callback type to data source process functions

runloop: replace struct btstack_data_source with btstack_data_source_t

runloop: set data source fd by new setter

runloop: set ds->process via setter

daemon: move examples from example/daemon to platform/daemon/example. fix mtk compile

use little/big_endian_read/store_16/24/32

add missing const specifiers

btstack-config.h -> btstack_config.h

use hci_transport_TYPE_instace() consistently. Fix iOS port build

fix missing bstack_ for struct data_source and struct timer. utils->btstack_util

prefix data_source_t and timer_source_t with btstack

prefix run_loop_ functions with btstack_

prefix debug with btstack_

hci_transport_h4.c -> hci_transport_h4_posix.c

separate platform specific code and ports for a particular setup