Update travis to build & push kabanero-utils image

[kvijai82]

We do this manually today. Will be good if this was an automated process.

[aadeshpa]

After checking the travis automated build and dockerhub automated build, it seems we can automate either when some PR gets merged to master or when a new tag is created after a release cut of pipelines.

In either of the cases, we have chicken and egg situation, because if. automated build of the kabanero-utils image is generated if release cut happens, then it has to be referenced with its specific digest value in all the pipelines, and hence we cannot cut release and then update the pipelines files with new image details.

Hence we need to have a way to build and push new kabanero-utils image first, then update the pipeline files references and then cut a release. I do not think Travis or Dockerhub automated build helps us achieve that. So, for now, I am preparing a script that will take 'kabanero dockerhub userid' , 'kabanero dockerhub password' , and 'kabanero utils image tagname' as inputs and the script will build the image and push it to the kabanero dockerhub.

[aadeshpa]

#382

[aadeshpa]

We made below decisions on brainstorming with @kvijai82 @brianxjx

1. For the release cut process we will try to bake in the build step of building the docker image kabanero-utils only on travis_tag which will be created if release cut happens. Once it is triggered we will build the docker image,
2. and then based on the digest values we would update all the tasks files to refer that image.

This way when the package.sh runs, it will get updated pipelines task files with correct imagename.

3. For the sourcecode repository we decide to add :latest as the image tag, instead of the digest value so the latest kabanero-utils image will be used.