Change image build logic

  * Implement pre-build.sh
    Due our CI strategy, its kinda hard to fetch all resources
    during docker build stage.
    split logic to:
    pre-build.sh - script, will be ran by jenkins,
      with ssh-agent wrapper
    extra/build.sh - script, will be ran during docker build
  * Merge RUN into one step, to reduce layer amount
  * Fix 'tempest' dependency - always isntall from local
    copy

Revert "Add authorization for gerrit repositories"
This reverts commit 920ac7ce0c2b9a67bdc9186cd5e75b0b2b93ed22.

Change-Id: I2edf0c6e337eef21b8f8f1d6c2f1636ccde60932
7 files changed