Bluetooth: Controller: Ext Adv Auxiliary PDUs with ticks_slot_window

Add implementation for Extended Advertising Auxiliary PDUs
to use ticks slot window feature.

This will allow the periodic scheduling of AUX_ADV_IND PDUs
to drift upto 10 ms advertising delay minus the ticks_slot
time reservation of the AUX_ADV_IND PDU when overlapping
with other states/roles that cannot be moved around, to
avoid skipping them.

Having an active Extended Advertising simultaneously with
an ISO Synchronized Receiver or Connected ISO connection
will now have less ISO SDU loss when using 10 ms ISO
intervals.

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>