Implement hybrid webapplication installation

Implement hybrid webapplication installation

Implemenation of hybrid package installation uses both
tpk and wgt steps, composing information from tizen
manifest file and w3c config.xml file. Installation
of hybrid has different flow so there is new installer
class introduced to avoid branching in steps. Instead
there is "hacky" branch in wgt-backend main() to choose
which step sequence to choose.

Requires:
 - https://review.tizen.org/gerrit/56503
 - https://review.tizen.org/gerrit/56506
 - https://review.tizen.org/gerrit/56795
 - https://review.tizen.org/gerrit/56918
 - https://review.tizen.org/gerrit/56920
 - https://review.tizen.org/gerrit/56921
 - https://review.tizen.org/gerrit/56724

Graph of targets (dependencies) changed to following:
  common_lib <-- tpk_lib
  common_lib <-- wgt_lib
  tpk_lib    <-- hybrid_lib
  wgt_lib    <-- hybrid_lib
  wgt_lib    <-- wgt_backend
  hybrid_lib <-- wgt_backend
  tpk_lib    <-- tpk_backend

Recovery for hybrid package will be added later
if possible.

Change-Id: I433f6030630f47c9f49025d89e267e5912bc78d9