This patch is adding the documentation for the IPMITool driver. This
covers some general overview, basic setup (prerequisites, how to enable)
as well as some advanced topics such as single/double bridge and protocol
version.
The IPMITool driver is rich and allows a lot of configuration, therefore
not all topics are addressed by this commit. TODOs were left in the
documentation (as comments) so we don't forget to address them later.
Partial-Bug: #1468710
Change-Id: Ife99de75a42d7048fd1ad31e220b5606a8fe81f0