bitbake: toaster: add Toaster UI interface

bitbake: toaster: add Toaster UI interface

Adding a new bitbake UI interface named 'toasterui'.

'toasterui' listens for events and data coming from a
bitbake server during a run, and records it
in a data store using the Toaster object model.

Adds a helper class named BuildInfoHelper that
reconstructs the state of the bitbake server and
saves relevant data to the data store.

Code portions contributed by Calin Dragomir <calindragomir@gmail.com>.

(Bitbake rev: 62200ff6694b21fbd5abf009a6f47ad93adf5309)

Signed-off-by: Alexandru DAMIAN <alexandru.damian@intel.com>
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>