GAP: LE scanning enabled not reset on HCI Reset -> can be enabled before HCI Power Up

Adds option to set the connection_scan_interval and connection_scan_window.

Adds functionality for setting the master-slave role policy. Fixes bug when handling HCI_EVENT_ROLE_CHANGE.

sm: moved sm_encryption_key_size, sm_authenticated, sm_authorization_state into gap.h

att_server: delete stored CCC values on pairing start

sm: enable check if LTK Request for LE Legacy Pairing comes from Central in LE Device DB, deny if not

sm: ENABLE_MICRO_ECC_FOR_LE_SECURE_CONNECTIONS enables micro-ecc software implementation

sm: use HCI commands to generate public key and calculate dhkey

hci: send le set event mask during init

l2cap-ertm: query extended features before opening l2cap ertm connection

hci: require ENABLE_LE_DATA_LENGTH_EXTENSION to enable max packet lenghts

hci: use max le data length if supported by controller

hci: check if LE Data Length commands are supported

hci: move le connection parameters for outgoing connections into hci_stack_t

hci: added hci_get_state()

gap: add gap functions for responding to legacy and ssp pairing requests

gap: provide gap_remote_name_request

gap: provide gap_inquiry_start + gap_inquiry_stop. emit GAP_EVENT_INQUIRY_COMPLETE

hci: controller to host flow control - set host size before enabling flow control

hci: Controller to Host Flow Control + docs

hci: fix compile

hci: reduced incoming prebuffer to 0 for LE-only, and outgoing to 0 if HAVE_HOST_CONTROLLER_API defined

hci: mark hci_write_local_name as Classic only, hci_le_generate_dhkey depend on HAVE_HCI_CONTROLLER_DHKEY_SUPPORT, reduce HCI Command Buffer size for LE only

h5: fix corruption of outgoing fragmented ACL packets.

h5: provide 2 byte post buffer for outgoing packets - used for 16-bit data integrity check