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>