Support creating Micro Bosh Stemcells

As a stemcell builder/sysadmin, I would like to have the ability to build micro bosh stemcells using the same stemcell builder process. 

Acceptance criteria:
All existing stemcell types are supported in the micro bosh mode.
Full end-to-end component level tests are present and passing.
Feature parity with old stemcell creation process. - vSphere only