odsComponentPipeline should populate context with contents from metadata.yml

[clemensutschig]

Is your feature request related to a problem? Please describe.
metadata.yml contains "configuration data" that is useful to a jenkins pipeline. Today only RM uses this infromation internally, but it should be exposed into the context.

Describe the solution you'd like
contents from metadata.yml should be injected into the default context

odsComponentPipeline(
  imageStreamTag: 'ods/jenkins-agent-base:4.x',
   ....
) { context ->

Describe alternatives you've considered
build it myself with yaml tooling (which needs even more validation as part of my pipeline)

[clemensutschig]

@metmajer @s2oBCN @serverhorror