Extract FetchApiClient interface

Extract FetchApiClient interface from FetchRestApiClient class and use
the new interface instead of the implementation. This allows to add
additional ways to send fetch and apply object messages.

Bug: Issue 15636
Change-Id: I68ec715f1f026ae4b61e05b332aeac8d5ca4c929
8 files changed
tree: 17248137eefcec07695f0774cff8e01a6571d393
  1. src/
  2. BUILD
  3. Jenkinsfile
  4. LICENSE