Move all advertising related code into one file

This patch moves btm_ble_adv_raddr_timer_timeout into same file that use
it. It also moves all structures related to multi-advertising into only
source file that uses them, to make sure noone uses them externally
while they undergo further refactoring.

Bug: 30622771
Change-Id: I721d222aa8f5317620c616cc59ee04b7b28a68b3