Refactor OpTestIPMI, add IPMIConsole class
Refactor OpTestIPMI, add IPMIConsole class

At the same time, fix some long lasting oddities around
IPMI console interaction and pexpect that were previously
solved by doing time.sleep(2).

Especially sensitive is the dance around initial connection
to the console, where we're trying to set the prompt and expect
everything correctly, *especially* if the prompt is already
set to our 'unique' prompt.

Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

open-power/op-test-framework,open-power/op-test-framework,open-power/op-test-framework