Bluetooth: controller: push topic branch to main

Pushes all work done in the topic-ble-llcp branch into main branch
This is a refactoring of the LL control procedures; the refactored
control procedures are hidden behind a KConfig option and
per default disabled

Goal of the refactoring:

close issue Link Layer Control Procedure overhaul #15256
make it easier to add/update control procedures
Refactoring consists in principal of writing explicit state machines
for the control procedures.
To reduce the risk of regression errors unit-tests have been added

Following control procedures are implemented:

Connection update procedure
Channel map update procedure
Encryption procedure
Feature exchange procedure
Version exchange procedure
ACL termination procedure
Connection parameters request procedure
LE Ping procedure
Data Length Update procedure
PHY update procedure
Min. nr. Of channels used procedure
Constant Tone extension request procedure

This is a joined work by the people listed in the signed-off-by
list (in alphabetical order)

Signed-off-by: Andries Kruithof <Andries.Kruithof@nordicsemi.no>
Signed-off-by: Erik Brockhoff <erbr@oticon.com>
Signed-off-by: Piotr Pryga <piotr.pryga@nordicsemi.no>
Signed-off-by: Szymon Janc <szymon.janc@codecoup.pl>
Signed-off-by: Thomas Ebert Hansen <thoh@oticon.com>
Signed-off-by: Tommie Skriver <tosk@demant.com>

Signed-off-by: Andries Kruithof <Andries.Kruithof@nordicsemi.no>