Add Get Channel Cipher Suites Command

Get Channel Cipher Suites Command is already implemented in
phosphor-ipmi-host, but it needs to be implemented in phosphor-ipmi-net
to be able to provide it as a pre-session command for discovering the
available cipher suites before initiating the session.

Without this, ipmitool will have a ten second timeout while attempting
to get the list of available cipher suites. At the same time, netipmid
will show the following messages in the journal:

    netipmid[8261]: Table: refuse to forward session-zero command

Tested: ran ipmitool and saw that it did not require a timeout
    ipmitool -U <user> -P <pw> -I lanplus -H <host> mc info

Change-Id: Iec1b6fc3262647b82acce0cba607b99e86b74985
Signed-off-by: Vernon Mauery <vernon.mauery@linux.intel.com>
3 files changed