beaker-wizard: Support for creating BeakerLib libraries

Added a new skeleton 'library' and a test type 'Library'
Adjusted autodetection for type and skeleton accordingly
Modified the Makefile skeleton to include library provides

Based on patches by Iveta Senfeldova and  Martin Kyral.

Bug: 910750
Change-Id: I1c31925c189866a5558992049e9e98b4aae75502