List the RAID devices.

    CLI Example:

    .. code-block:: bash

        salt '*' raid.list

def list_():
    '''
    List the RAID devices.

    CLI Example:

    .. code-block:: bash

        salt '*' raid.list
    '''
    ret = {}
    for line in (__salt__['cmd.run_stdout']
                    (['mdadm', '--detail', '--scan'],
                     python_shell=False).splitlines()):
        if ' ' not in line:
            continue
        comps = line.split()
        device = comps[1]
        ret[device] = {"device": device}
        for comp in comps[2:]:
            key = comp.split('=')[0].lower()
            value = comp.split('=')[1]
            ret[device][key] = value
    return ret