GSoC '19: artifact promotion in Jenkins' pipeline. (Coding Phase-I)

Tasks to be completed during the first coding phase.

1) Detaching the required modules from hudson.plugins.promoted_builds(and refactoring those) for pipeline compatibility.(Includes 8-10 such modules on which the promoted_builds.condition rely).

2) Detach the extension points from promoted_builds.condition package for pipeline compatibility.

Done in two Stages:

1. Refactor four such conditions(Up/Downstream, Manual and Self Promotion Conditions).
2. Refactor the remaining extensions points and also make the two points inside integrations.dsl package pipeline
   compatible(ReleasePromotionCondition and JobDslManualCondition).

3) Create new customs steps for the new plugin. (Also Done in Two stages as described in the task.)