Return info on all groups

    CLI Example:

    .. code-block:: bash

        salt '*' group.getent

def getent(refresh=False):
    '''
    Return info on all groups

    CLI Example:

    .. code-block:: bash

        salt '*' group.getent
    '''
    if 'group.getent' in __context__ and not refresh:
        return __context__['group.getent']

    ret = []
    for grinfo in grp.getgrall():
        ret.append(info(grinfo.gr_name))

    __context__['group.getent'] = ret
    return ret