hci: use hci opcode in handle_command_complete_event

remove <stdio.h>, <stdlib.h> and printf from most core files

hci: extract handle_command_complete_event

hci: mark hci_handle_remote_features_xxx functions as Classic only

hci: fix bad assignment

gap: only accept authentication if we did send an auth request

hci: request authentication after read encryption key size if not already authenticated

hci: extract hci_handle_read_encryption_key_size_complete

gap: disconnect if remote does not support SC but link key key indicates SC was used for pairing

hci: use ERROR_CODEs instead of constants, set connection>state = SENT_DISCONNECT upon sending HCI Disconnect

hci: read remote features page 2

hci: track remote feature Secure Connections (Host) and (Controller)

hci: extract handle_remote_features_page_x

hci: hci_remote_ssp_supported requires SSP support in Controller and Host

hci: read remote extended features (features page 1) if possible

hci: track remote extended features flag

hci: move eSCO remote feature into remote supported feature bit field

hci: extract hci_handle_remote_features_received

hci: split request remote supported features into read features page 0, 1, and 2

hci: clarify BONDING_REMOTE_SUPPORTS_SSP as BONDING_REMOTE_SUPPORTS_SSP_CONTROLLER

gap: Detect Secure Connection -> Legacy Connection Downgrade Attack (BIAS)

gap: add gap_secure_connections_enable

fix logic to send Write Secure Connections Host Enable command

gap: add gap_secure_connections_enable

Revert "hci: write secure connections host enable if command supported"

This reverts commit 47bc3ebbd9c7203e97682307a2d63374390b5ae3.

hci: write secure connections host enable if command supported