These functions are only used by nm-meta-setting-desc.c. Make them internal.
Unfortunately, they are part of "common.h" which cannot be used without
the rest of nmcli. Still todo.
This part contains static functions and variables to describe
settings. It is distinct from the mechanism to use them, or
access them.
Split it out.
It still uses clients/cli/common.h and clients/cli/utils.h
which shall be fixed next.
