To allow users to install asn1c quickly in install, make this directory
to allow standalone execution of install_asn1c_from_source.

The instructions are now:
sudo ls  # open sudo session, required by install_asn1c_from_source
. oaienv # read of default variables
. cmake_targets/tools/build_helper # read in functions
install_asn1c_from_source # install

CMake now takes the option ASN1C_EXEC to select an asn1c to use for
compilation. For instance, run with
cmake .. -GNinja -DASN1C_EXEC=/opt/asn1c/bin/asn1c
or
./build_oai --cmake-opt -DASN1C_EXEC=/opt/asn1c/bin/asn1c
to select the alternative asn1c. For instance, this is important for the
CI to allow to build multiple versions of OAI in parallel that might use
different commits of OAI.

Further, this patch introduces functionality to check for the support of
asn1c options that we require, and alerts the user if they are missing,
alongside a message of how to resolve the problem.

We don't work much on asn1c. The version we use has several bugs.
There is an active community out there that fixes bugs and improves
asn1c. Let's use their version.

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

integration_2023_w21

See merge request oai/openairinterface5g!2128

* !2097 Fix: NR UE timing adjust
* !2100 CI: AW2S pipeline - iperf test added, modifs in OC projects usage
* !2119 Set kernel parameters for X4x0
* !2121 Fix regression pdu session release
* !2124 handle --disable-stats in rrc gNB
* !2125 Tutorials: minor updates on NR SA Tutorial
* !2126 bugfix for PRACH format C2 at UE
* !1964 Merge secu osa into openair3/SECU
* !2101 Use F1 internally: UE Context Release
* !2120 Use F1 internally: UE Context Modification
* !2129 Adding a check to avoid having more logical antenna ports than physical in config file

There are a number of timers in RRC. Those are not or only partially
implemented, and certainly don't work in F1. Hence, remove them to
replace with a better implementation later.