Fix fake bmc driver.

The fake BMCDriver implementation accidentally copied, rather than
inherited from, the base class definition.

Change-Id: Ic2552dfdc93ad262c6ce04126f1133cd543bd800
Update proposed API.

Make it more resource-oriented.

Rename iface -> port, and add the chassis resource.

Add some JSON examples, and some proper RST formatting.

Change-Id: I1c434e92c1b7b6d9b61f2332ca0e1c425fee14b4