[SAC] Handling step down from OSGeo admins

I just got a reply from crschmidt mentioning he's not doing
OSGeo activities anymore, so we've to decide how to deal with
steps down.

Problem is that user "crschmidt" has traces of activities
in many places and also has ssh access to machines and even
sudo privileges. Also right now the associated email is
outdated/wrong. How do we deal with such situations ?

Note that:

- There's currently no way to "block" an account
   (https://trac.osgeo.org/osgeo/ticket/1680 is aimed at this)

- The tool to remove an account from the "shell" group does not work:

- We don't have a way to find all accounts that have not been
   used for a long time:

I'm hoping the new contractor can take care of these issues...