As a user, I would like to be able to access semvers used for promotion for non-docker components

[jcantosz]

For promotion pipelines, it would be useful for the promote to use modular components so that items like the currSemVers can be accessed and used to promote non-docker artifacts (ie. npm, nuget, python, etc) when an image is promoted without duplicating this code.

In the simplest sense this could be done like:

class BoxPromote {
  def getCurrentSemanticVersion(){ ... }
  def getNextSemanticVersion(){ ... }
  def hasVersionChanged(){ ... }
}

with a subclass like this using it as it likes:

class MyPromote extends BoxPromote {
   @Override
   def init(){
    def currVer = getCurrentSemanticVersion()
    def nextVer = getNextSemanticVersion()
    Config.pipeline.env['VERSION'] = (hasVersionChanged()) ? currVer : nextVer
  }
}