Make singleton the default scope for DI

Change-Id: I74fe40c0739e03d11ac047786530e8f0d24178d9
DI for classes that don't implement an interface

Change-Id: I0c7195289b3aecd2c6262fae12c0ea55c2faf9c7
Merge changes I0c719528,I74fe40c0 into wip/editorcampaigns

* changes:
  DI for classes that don't implement an interface
  Make singleton the default scope for DI