Surprisingly, it touches every part of openair3, and most of the prototype.
Moreover, a special attention have been put to callback review.
However, there are still places to fix or review indicated by FIXME

This patch adds esm_data_t parameter to ESM functions.
This fixes a bug where the old _esm_data was redefined in all .o

Signed-off-by: Frédéric Leroy <frederic.leroy@b-com.com>

This patch merely adds a "user" object in all nas_* functions.
This don't move any data structure.
It allows next patches to be nicely split.

Signed-off-by: Frédéric Leroy <frederic.leroy@b-com.com>

The code was changing the rnti in the red-black tree without
removing/reinserting the context. This is wrong because the
rnti is a key of the red-black tree and you cannot change the
key in a stored item at will.

There are also modifications of the function mac_eNB_rrc_ul_failure
which has to remove the UE in any case.

And rrc_mac_remove_ue has been changed for the case where
the UE is not found.