Split PAM items into their own separate struct. To trim down the number of methods on `PamShared`, this puts all the Items into their own struct(s). This also makes the split between authtok/authtok_item easier to understand.

FROM docker.io/debian:stable

RUN apt-get -y update \
    && apt-get -y upgrade \
    && apt-get install -y cargo mercurial \
    && apt-get clean