add multipath testing once trigger-action code is in

[trgill]

Right now, we don't have the LVM and other modules in place... except the mpath module, but that one also requires some more finishing once we have trigger-action code in - this is the part that I'm working on right now so we can dive into modules more.

Currently, SID only collects very basic "holders/slaves" structure available from /sys that can be done without module-specific code. So for further tests, we need to wait a bit for the other parts to land so we can glue them together.

We will also need some way to present and remove devices for the system, so we can also test how SID behaves when devices are hotplugged and then disconnected or when being temporarily inaccessible. Can we do this directly or do we need to simulate?

Originally posted by @prajnoha in #53 (comment)

[trgill]

@bmarzins Just FYI - we've got Jenkins nodes with multipath devices setup.